leslie's EARTH and SKY science weblog

045 Why We Age: Cloze Test and Crossword Puzzle

2005-03-13T03:19:00.000-08:00

Please click here for a Cloze Test on Why We Age. If you send me an email, I'll be quite happy to send you a crossword about this topic. Please put '045 Why We Age: Crossword Puzzle' in the Subject line.

044 Why We Age: HotSpots and Advanced VocabBox

2005-03-13T03:11:00.000-08:00

age
animals
a scientist
human longevity
Steve Austad
Barshop Institute for Longevity and Aging Studies
San Antonio
Texas
prone to illness
muscles
mysteries in biology
humans' average lifespan
enchilada
biomedicine

043 Why We Age: HotSpots and Intermediate VocabBox and Glossary and Vocabulary Double-Check

2005-03-12T12:36:00.000-08:00

age: 'age' is a verb here, meaning 'to become old, to show the effects or the characteristics of increasing age'
animals: any of a kingdom (Animalia) of living things including many-celled organisms and often many of the single-celled ones (as protozoans) that typically differ from plants in having cells without cellulose walls, in lacking chlorophyll and the capacity for photosynthesis, in requiring more complex food materials (as proteins), in being organized to a greater degree of complexity, and in having the capacity for spontaneous movement and rapid motor responses to stimulation; a human being is considered chiefly as an animal by physical or nonrational factors
a scientist: here by science we can understand any one or any combination of animal biology (zoology), anthropology (physical), biochemistry,
Biomathematics, Biometrics, Biophysics, Cell biology, Ethology, Genetics,
Human biology, Human physiology, immunology, insect biology, medicine,(Entomology), microbiology, Molecular biology, palaeontology, pharmacology, plant biology (botany), radiobiology, symbiosis, virology, other biological specialities
human longevity: its study needs a multidisciplinary approach, integrating biological knowledge (studies on human biology and animal models) with demographic research.
Steve Austad: Dr. Austad's research interests focus on the biology of aging in humans, mammals, and birds. Both laboratory and field studies are used to address questions concerning the relationship between reproduction, diet, sex, and aging.
Barshop Institute for Longevity and Aging Studies: its goal is to identify the genes and underlying biological processes that enhance healthy aging and longevity
San Antonio: is one of America's most historic cities, with its Spanish roots reaching back to 1691 when an exploratory party, called an "entrada," headed by Domingo Teran de los Rios, made its way north out of Mexico where the Spanish had already been firmly entrenched for more than 150 years
Texas: is the largest of the continual continental states and the second largest overall. Alaska is the only state larger than Texas. The population of Texas is currently estimated at more than 22,000,000.
prone to illness: having a natural tendency to be sick more often than mates because they are biologically more sensitive than others
generalized decline in function: the functioning of your body depends on a range of biochemical reactions and counter reactions. With aging some of the body functions slow down, and are performed less perfectly.
muscles: muscles # 2 muscles # 3 muscles # 4 muscles # 5 a tissue composed of bundles of elongated cells capable of contraction and relaxation to produce movement in an organ or part
mysteries in biology: one of the mysteries of biology goes like this 'How does tooth enamel, the hardest mineral in the mammalian body, emerge from soft, organic gum tissue?', and there are many more.
humans' average lifespan: with few exceptions, 30,000 days is the average human lifespan - 40,000 if you're lucky. However, two-thousand years ago average life expectancy was less than 20 years or about 7,000 days. It is difficult to imagine, but most of our ancestors kicked the bucket before our modern legal drinking age.
enchilada: a Mexican dish consisting of a tortilla fried in hot fat, filled with meat, and served with a chilli sauce
biomedicine: the medical study of the effects of unusual environmental stress on human beings

So far so good. Now let's see the same vocabulary explanation together with the original text. Please click here for a GLOSSARY.

Now that you know everything about the topic, it is high time to test your vocabulary. Please click here for a DOUBLE-CHECK.

042 Why We Age: Text and HotSpots

2005-03-12T12:00:00.000-08:00

Why We Age

All animals age. But they age at different rates. Mice live for about three years, bats nearly 40 years and humans to about 110. We ask a scientist why we all age -- next on Earth and Sky.

Wednesday, March 2, 2005

Can bats be the key to human longevity?

JB: This is Earth and Sky. A listener writes, "Why do we age? Do our bodies somehow lose their ability to fight off disease?"

DB: We asked Steve Austad, at the Barshop Institute for Longevity and Aging Studies in San Antonio, Texas. He says that, although people do tend to become more prone to illness as they age, aging is much more than that.

Steve Austad: If you think about it, you know nobody that's 50 can sprint as fast as they could when they were 20, even if they're the healthiest 50 year old in the world. And the difference between that -- what they were at 20 and what they are at 50 -- that's what aging is all about. It's that generalized decline in function. And it just isn't your muscles. It's everything. And to me this is one of the most exciting mysteries in biology because if you think about it, animals are almost defined . . . by the fact they can repair damage that happens to them. And yet, aging . . . is the accumulation of damage that for some reason our bodies just simply refuses to repair.

JB: Austad says that curing one disease at a time -- such as heart disease or cancer -- might only extend humans' average lifespan by 5 or 10 years. But the best way to preserve human health would be to slow down aging.

Steve Austad:. . . It's the big enchilada for me, in the whole field of biomedicine, is figuring out what causes it and then figure out whether we might be able to manipulate the rate at which it occurs.

DB: More from Steve Austad next time. We're Block and Byrd for Earth and Sky.

Author(s): Marc Airhart

More information about this topic

Please let us know what you think!

Tuesday, March 1, 2005 • Thursday, March 3, 2005

© 2005 Byrd & Block Communications Inc. Permission to use, copy and distribute these materials without fee is hereby granted, provided that the above copyright notice appear in all copies and the materials are not redistributed for profit.

041 Why We Age: Sound and Text

2005-03-12T11:49:00.000-08:00

Click here for LISTENING

Click here for original article WHY WE AGE

Click here for PICTURE

Can bats be the key to human longevity?
JB: This is Earth and Sky. A listener writes, "Why do we age? Do our bodies somehow lose their ability to fight off disease?"

Steve Austad:. . . It's the big enchilada for me, in the whole field of biomedicine, is figuring out what causes it and then figure out whether we might be able to manipulate the rate at which it occurs.

DB: More from Steve Austad next time. We're Block and Byrd for Earth and Sky.

Author(s): Marc Airhart

More information about this topic

Please let us know what you think!

Tuesday, March 1, 2005 • Thursday, March 3, 2005

040 Global Fresh Water: Cloze Test and Crossword Puzzle

2005-03-10T12:12:00.000-08:00

Please click here for a Cloze Test on Global Fresh Water. If you send me an email, I'll be quite happy to send you a crossword about this topic. Please put '040 Global Fresh Water: Crossword Puzzle' in the Subject line.

039 Global Fresh Water: HotSpots and Advanced VocabBox

2005-03-10T12:07:00.000-08:00

global fresh water
access to safe water
a scientist hydrological phenomena
managing the global supply of fresh water
Pacific Institute for Studies in Development, Environment, and Security
global climate change
fresh water ecosystems
climate and water
powering hydroelectric dams
producing steel
producing plastic
irrigation drip irrigation
hydrologic cycle
a river
a watershed

038 Global Fresh Water: HotSpots and Intermediate VocabBox and Glossary and Vocabulary Double-Check

2005-03-10T12:00:00.000-08:00

global fresh water: water is fundamental to human life but is often a scarce resource. Demand for fresh water is rising: the consequence of a growing world population and increasing demand in developing countries.
a billion: in America, is a thousand million. That would be written 1,000,000,000. Interestingly, in England, the British define a billion as a million million. That would be 1,000,000 times 1,000,000 which would be written as 1,000,000,000,000.
access to safe water: water covers more than 70% of the earth’s surface and would seem to be an inexhaustible resource. Considering that more than 97% of this water is salt water existing in our Ocean’s and 1.8% locked in our polar ice caps. This leaves less than 1 % of all the earth’s sources as fresh water to sustain all living things..... including humanity. Of this it is unclear how much remains unpolluted.
a scientist: hydrologists study the distribution of water. They may research the flow or discharge of water along a river or over a dam. Hydrologists often work as a team with other scientists. Hydrologists are interested in lake or river levels and how these levels affect commerce, shoreline erosion, etc. Some hydrologist work as researchers in universities. Others may find employment with engineering firms that design and build sewers, channels, and other water related structures.
global supply of fresh water: of all water on earth, 97.5% is salt water, and of the remaining 2.5% fresh water, some 70% is frozen in the polar icecaps.
Dr. Peter Gleick: is co-founder and President of the Pacific Institute for Studies in Development, Environment, and Security in Oakland, California. His research and writing address the critical connections between water and human health, the hydrologic impacts of climate change, sustainable water use, privatization and globalization, and international conflicts over water resources.
Pacific Institute for Studies in Development, Environment, and Security: is dedicated to protecting our natural world, encouraging sustainable development, and improving global security. Founded in 1987 and based in Oakland, California, it provides independent research and policy analysis on issues at the intersection of development, environment, and security.
Oakland: a port and industrial centre in West California on San Francisco Bay. It was damaged by earthquake in 1989.
California California # 2
global climate change: climate is the average pattern of weather over the long term. The earth’s climate has warmed and cooled for millions of years, since long before we appeared on the scene. There’s no doubt that the climate is growing warmer currently; indications of that change are all around us.
water systems: the public drinking water systems provide drinking water to 90 percent of the population [USA].
how much water we get: less than 1% of the world's fresh water (or about 0.007% of all water on earth) is readily accessible for direct human uses.
when we get it: the amount of fresh water is, of course, dependant on rainfall and this varies according to the geographic location of the island and climate conditions. There is normally a “wet season” that replenishes water supplies for the subsequent dry season.
where we get it: it is found in lakes, rivers, reservoirs and in underground sources.
water quality we get: contamination is the impairment of water quality to a degree that reduces the usability of the water for ordinary purposes or creates a hazard to public health through poisoning or the spread of diseases.
climate and water: the distribution of water within the Earth system is vitally important for humankind and life in general. Of the two most important climate parameters, temperature and precipitation, the latter simply is water and the former is dominated by water in its role of distributing heat over the planet.
advancing technologies: the sound management of water resources through
advancing water resources and related environmental research, promoting water resources education, improving exchanges of information and expertise, networking with other organizations who share common interests and goals providing an international forum on water resource issues
powering hydroelectric dams: hydro-electric power plants convert the kinetic energy contained in falling water into electricity. The energy in flowing water is ultimately derived from the sun, and is therefore constantly being renewed. Energy contained in sunlight evaporates water from the oceans and deposits it on land in the form of rain. Differences in land elevation result in rainfall runoff, and allow some of the original solar energy to be captured as hydro-electric power.
irrigation: is a system of watering crops and plants using ditches and small canals to run water from rivers to plants.
susceptible: hypersensitive to external changes
upstream: in a direction opposite to that of a stream's current
hydrologic cycle: Earth's water is always in movement, and the water cycle, also known as the hydrologic cycle, describes the continuous movement of water on, above, and below the surface of the Earth. Since the water cycle is truly a "cycle," there is no beginning or end. Water can change states among liquid, vapor, and ice at various places in the water cycle, with these processes happening in the blink of an eye and over millions of years.
a river: it is fresh water flowing across the surface of the land, usually to the sea. It flows in a channel. The bottom of the channel is called the bed and the sides of the channel are called the banks.
a watershed: it is the area of land where all of the water that is under it or drains off of it goes into the same place.
affect: to produce an effect upon, as a: to produce a material influence upon or alteration in b: to act upon (as a person or a person's mind or feelings) so as to bring about a response; influence

So far so good. Now let's see the same vocabulary explanation together with the original text. Please click here for a GLOSSARY.

Now that you know everything about the topic, it is high time to test your vocabulary. Please click here for a DOUBLE-CHECK.

037 Global Fresh Water: Text and HotSpots

2005-03-10T04:34:00.000-08:00

Global Fresh Water

Today, more than a billion people on Earth lack access to safe water. Up next -- a scientist talks about managing the global supply of fresh water in this century -- after this on Earth and Sky.
Tuesday, March 1, 2005

JB: This is Earth and Sky, on managing fresh water, globally.

DB: Dr. Peter Gleick is Director of the Pacific Institute for Studies in Development, Environment, and Security in Oakland, California. He talked to us about Earth's supply of fresh water in this century.

Peter Gleick: Without a doubt, global climate change is a real problem. And without a doubt global climate change is going to affect our water systems - how much water we get, when we get it, where we get it, the water quality we get -- and we're not prepared to deal with that yet. We're not really thinking about climate and water together.

JB: He says the challenge facing us is to use fresh water efficiently -- while advancing technologies that let us do the things we need to do with less water. That's less water for things like powering hydroelectric dams, producing steel and plastic -- and irrigation. Irrigation alone accounts for more than seventy percent of the fresh water humans use.

DB: But water crosses borders, and that's why, says Gleick, decisions concerning fresh water management are increasingly becoming political issues.

Peter Gleick: One of the great challenges with water is that, in a sense, we all live downstream. We're all susceptible to people upstream from us doing something to water -- either in a hydrologic cycle, in a river, in a watershed. The things we do affect other people who use that water.

036 Global Fresh Water: Sound and Text

2005-03-10T04:10:00.000-08:00

Tuesday, March 1, 2005

Click here for LISTENING

Click here for original article Global Fresh Water

Click here to view PICTURE

JB: This is Earth and Sky, on managing fresh water, globally.

DB: But water crosses borders, and that's why, says Gleick, decisions concerning fresh water management are increasingly becoming political issues.

JB: For links to more about global fresh water, come to earthsky.org. We're Block and Byrd for Earth and Sky.

Author(s): Eleanor Imster

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Monday, February 28, 2005 • Wednesday, March 2, 2005

035 Zodiacal Light: Cloze Test and Crossword Puzzle

2005-03-03T11:35:00.000-08:00

Please click here for a Cloze Test on Zodiacal Light. If you send me an email, I'll be quite happy to send you a crossword about this topic. Please put '035 Zodiacal Light: Crossword Puzzle' in the Subject line.

034 Zodiacal Light: HotSpots and Advanced VocabBox

2005-03-03T03:28:00.000-08:00

zodiacal light
dawn
Southern Hemisphere
planets and moons in our solar system
planets and moons in our solar system # 2
orbit the sun
dust in the plane of the solar system
sunlight bouncing off dust grains
ecliptic
twilight
equator

033 Zodiacal Light: HotSpots and Intermediate VocabBox and Glossary and Vocabulary Double-Check

2005-03-03T03:26:00.000-08:00

zodiacal light: it is a faint, roughly triangular shaped glow of light extending away from Sun; the spectrum of the zodiacal light is the same as the solar spectrum, reinforcing the deduction that it is merely sunlight reflected by dust in the plane of the planets

dawn: time at which there is enough light for you to distiguish objects and when you can start outdoor activities

Southern Hemisphere: the part of the Earth's surface that is south of the equator; it contains four continents [Africa, Australia, South America, and Antartica] separated by four oceans [South Atlantic Ocean, Pacific Ocean, Indian Ocean, and Antarctic Ocean]

eerie pyramid of light: mysteriously frightening light of triangular shape

planets and moons: a moon is a natural satellite rotating around a planet; while moons vary in size, each moon is much smaller than its planet; almost 140 moons are known in the Solar System; several moons are larger than the planet Pluto and two moons are larger than the planet Mercury; there also are many small moons that may be asteroids captured by their planets

solar system: consists of an average star we call the Sun, the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto; it includes the satellites of the planets; numerous comets, asteroids, and meteoroids; and the interplanetary medium

orbit the sun: the planets, most of the satellites of the planets and the asteroids revolve around the Sun in the same direction, in nearly circular orbits; when looking down from above the Sun's north pole, the planets orbit in a counter-clockwise direction;

nearly flat plane: the planets orbit the Sun in or near the same plane, called the ecliptic

dust in the plane of the solar system: the solar system is always plowing through interstellar material; the Sun's giant magnetic field thwarts much of the dust from entering the solar system but the magnetic field weakens periodically, on a cycle that lasts roughly 22-years; the cycle is related to an 11-year cycle of sunspot activity

sunlight bouncing off: zodiacal light is produced by sunlight reflecting off particles of dust present throughout much of the solar system; the amount of material needed to produce the observed zodiacal light is amazingly small
dust grains: if it were in the form of 1mm particles each with the same albedo (reflecting power) as Earth's moon each particle would be 5 miles from its neighbours

ecliptic: it is the geometric plane that contains the orbit of the Earth; the orbits of most planets in the Solar System lie very close to it

twilight: twilight is the time before sunrise and after sunset when sun light reflected from particles in the upper atmosphere illuminates the lower atmosphere and the surface of the earth

northern part of Earth's globe: it is the half of a planet's surface (or celestial sphere) that is north of the equator; on Earth, the Northern Hemisphere contains most of the land and population

equator: it is located at zero degrees latitude; the equator runs through Indonesia, Ecuador, northern Brazil, the Democratic Republic of the Congo, and Kenya, among other countries; it is 24,901.55 miles (40,075.16 kilometers) long; on the equator, the sun is directly overhead at noon on the two equinoxes - near March and September 21; the equator divides the planet into the Northern and Southern Hemispheres

So far so good. Now let's see the same vocabulary explanation together with the original text. Please click here for a GLOSSARY.

Now that you know everything about the topic, it is high time to test your vocabulary. Please click here for a DOUBLE-CHECK.

032 Zodiacal Light: Text and HotSpots

2005-03-03T03:21:00.000-08:00

Zodiacal Light

This is the best time of year to see the zodiacal light before dawn from Earth's Southern Hemisphere -- and in the evening from the northern part of the globe. The zodiacal light -- after this on Earth and Sky.

Monday, February 28, 2005

JB: This is Earth and Sky, on an eerie pyramid of light -- seen before sunrise or after sunset -- called the zodiacal light.

DB: The planets and moons in our solar system orbit the sun in a nearly flat plane. And there's also dust in the plane of the solar system. The zodiacal light is really sunlight bouncing off these dust grains in nearby space. Since this dust orbits in the same plane as the planets and moons near us in space, we see the zodiacal light along the same path across our sky traveled by the sun, moon and planets.

JB: This pathway from east to west across our sky is called the ecliptic. And if you'll think of the ecliptic or plane of the solar system turned on its side -- stretching up above the sunrise or sunset point -- you'll have an idea of what the zodiacal light looks like. It's like a cone or pyramid of light. You won't see it in twilight -- but instead in the hour before morning twilight begins -- or in the hour after evening twilight ends.

DB: You need a dark sky to see the zodiacal light. Late February, March and April are the best time to see it before dawn from Earth's southern hemisphere. At the same time, these months are the best time to see the light in the evening from the northern part of Earth's globe.

JB: The closer you are to the equator, the easier it is to see the zodiacal light. While driving on country roads, people sometimes mistake the zodiacal light for the light of a city or town just beyond their horizon.

DB: For today, that's our show. We're Block and Byrd for Earth and Sky.
Author(s): Deborah Byrd

Please let us know what you think!
Sunday, February 27, 2005 • Tuesday, March 1, 2005

031 Zodiacal Light: Sound and Text

2005-03-03T02:49:00.000-08:00

Monday, February 28, 2005

Click here for LISTENING

Click here for original article ZODIACAL LIGHT

JB: This is Earth and Sky, on an eerie pyramid of light -- seen before sunrise or after sunset -- called the zodiacal light.

DB: For today, that's our show. We're Block and Byrd for Earth and Sky.
Author(s): Deborah Byrd

Please let us know what you think!
Sunday, February 27, 2005 • Tuesday, March 1, 2005

030 Internal Heat: Cloze Test and Crossword Puzzle

2005-03-01T13:11:00.000-08:00

Please click here for a Cloze Test on Internal Heat. If you send me an email, I'll be quite happy to send you a crossword about this topic. Please put '030 Internal Heat: Crossword Puzzle' in the Subject line.

029 Internal Heat: HotSpots and Advanced VocabBox

2005-03-01T04:08:00.000-08:00

internal heat
inside Earth
energy
move continents
cause earthquakes
build mountains
the Earth's interior
cloud of gas
dust in space
particles
planetesimals
rocks
Earth's crust
interior
radioactive decay
disintegration of natural radioactive elements
subatomic particles
collide
energy of motion is converted to heat
primary heat source
shifting of land plates
sun's heat
weather
erosion

028 Internal Heat: HotSpots and Intermediate VocabBox and Glossary and Vocabulary Double-Check

2005-03-01T03:39:00.000-08:00

internal heat: the thermal energy produced and stored inside the earth
inside Earth: the inner core, the outer core, the mantle, and the lower layers of the crust
inner core: it is thought to be a solid sphere of iron and nickel; there are conflicting theories concerning its size but its radius must be about 775 miles, i. e. some 1,250 kilometers; it exists under fantastic pressure, i. e. some 3 million times that of atmospheric pressure at sea-level; its temperature is about 11,100 F, i. e. 6,150 C, and it is about the same as the temperature of the surface of the sun
outer core: it is made up of liquid iron and nickel; the motion of the liquid metals on the solid inner core produces the magnetic field of the earth [this is what scientists call the dynamo theory]; it is about 2,700 miles, i. e. 4,350 kilometers thick; the temperature of the outer core is about 7,200 to 9,100 F, i. e. 4,000 to 5,000 C
mantle: it is a plastic layer of rock which extends from the mantle down to the outer core; the rock is mainly olivine, i. e. magnesium iron silicate; near the mantle the molten rock is thick or even brittle; deeper down it is thinner liquid; the mantle is heated by the decaying of radioactive elements
crust: it is only 5 miles, 8 kilometers, thick beneath the oceans, and 25 miles, i. e. 40 kilometers, thick under the continents; it is devided into immense 'tectonic' plates; it is composed mainly of granites under the continents, and basalts under the oceans
energy: the fundamental energy source within the Earth is heat, primarily provided by radioactive decay in the mantle
move continents: the liquid mantle is moved by the heat as any boiling liquid; moved by convection currents in the liquid mantle the tectonic plates slowly grind against each other in a process known as 'continental drift'
cause earthquakes: sites where continental plates meet are areas of intense geologic activity, including earthquakes
build mountains: sites where continental plates meet are areas of intense geologic activity, including building mountains
Earth's interior: the inner core, the outer core, the mantle, and the lower layers of the crust
cloud of gas and dust in space: most scientific work has centered on the theory that the sun and planets were formed by the slow condensation of a gigantic cloud of dust and gas
particles: until 1932, the "elementary" particles were the electron, proton, and neutron; we now know of hundreds of other elementary particles
planetesimals: nearly 5 billion years ago, the solar system was just a giant cloud of gas; gravitational forces made the cloud contract; the cloud was not homogenous, therefore not only one object was formed in the middle of the cloud (the Sun), but a large number of small objects called planetesimals, or planet building blocks, formed around the Sun
rocks: minerals that make up part of the earth's crust
Earth's crust: the upper layer of the Earth, is not always the same; crust under the oceans is only about 8 km thick while continental crust can be up to 40 km thick; also, ocean crust is made of denser minerals than continental crust
interior: a part, surface, or region that is inside the Earth
radioactive decay: materials that emit alpha, b beta, and g gamma radiation are said to be radioactive and to undergo radioactive decay
disintegration of natural radioactive elements: radioactivity is the property of some elements or isotopes to spontaneously emit particles of energy by the disintegration of their atomic nuclei; this process is known as radioactive decay; as a sample of radioactive material decays, it becomes stable and nonradioactive; the amount of time it takes for half of a sample of radioactive material to decay into a stable substance is called its half-life
subatomic particles: in physics, a subatomic particle is a particle smaller than an atom; these include atomic constituents such as electrons, protons, and neutrons (protons and neutrons are actually composite particles, made up of quarks), as well as particles produced by radiative and scattering processes, such as photons, neutrinos, and muons
zip away: generally it means 'it is safe to jump'; here in this context it means 'escape'
collide: crash together with a violent impact
energy of motion is converted to heat: the Law of Conservation of Energy states that energy is neither created nor destroyed but changes from one form to another; the total amount of energy stays the same
primary heat source: this is the main source of energy inside the earth
shifting of land plates: it refers to the drifting of tectonic plates
sun's heat: the sun's energy that is radiated to, and trapped in the earth
weather: the day-to-day meteorological conditions, esp. temperature, cloudiness, and rainfall
erosion: the wearing away of rocks and other deposits on the earth's surface by the action of water, ice, and wind

So far so good. Now let's see the same vocabulary explanation together with the original text. Please click here for a GLOSSARY.

Now that you know everything about the topic, it is high time to test your vocabulary. Please click here for a DOUBLE-CHECK.

027 Internal Heat: Text and HotSpots

2005-03-01T02:50:00.000-08:00

Internal Heat

The heat inside Earth contains enormous amounts of energy -- enough to move continents, cause earthquakes and build mountains. Up next -- we talk about where all this heat comes from -- after this on Earth and Sky.
Sunday, February 27, 2005

DB: This is Earth and Sky. A listener's question, "What is the source of the heat in the Earth's interior?"

JB: A lot of Earth's heat is thought to be leftover from when our planet formed, four-and-a-half billion years ago. Earth is thought to have arisen from a cloud of gas and dust in space. Solid particles, called "planetesimals" condensed out of the cloud -- they're thought to have stuck together and created the early Earth. Bombarding planetesimals heated Earth to a molten state. So Earth started out with a lot of heat -- but, even now, new heat is being produced.

DB: Many of the rocks in Earth's crust and interior undergo a process of radioactive decay. That's the disintegration of natural radioactive elements. This process produces subatomic particles that zip away -- and later collide with surrounding material inside the Earth. Their energy of motion is converted to heat -- to create Earth's primary heat source. Without radioactive decay, Earth would have fewer volcanoes or earthquakes -- less shifting of land plates and building of vast mountain ranges.

JB: The heat energy produced by Earth is enormous, but it's 5000 times less than what Earth receives from the sun. The sun's heat drives the weather and ultimately causes erosion.

DB: So while the Earth's heat builds mountains, the sun's heat destroys them. With thanks to the National Science Foundation, we're Block and Byrd for Earth and Sky.

Author(s): Bizy Kubala, Mohan Rao, Marc Airhart, Deborah Byrd

Please let us know what you think!

Saturday, February 26, 2005 • Monday, February 28, 2005

026 Internal Heat: Sound and Text

2005-03-01T02:42:00.000-08:00

Click here for LISTENING

Click here for original article INTERNAL HEAT

DB: This is Earth and Sky. A listener's question, "What is the source of the heat in the Earth's interior?"

JB: A lot of Earth's heat is thought to be leftover from when our planet formed, four-and-a-half billion years ago. Earth is thought to have arisen from a cloud of gas and dust in space. Solid particles, called "planetesimals" condensed out of the cloud -- they're thought to have stuck together and created the early Earth. Bombarding planetesimals heated Earth to a molten state. So Earth started out with a lot of heat -- but, even now, new heat is being produced.

DB: Many of the rocks in Earth's crust and interior undergo a process of radioactive decay. That's the disintegration of natural radioactive elements. This process produces subatomic particles that zip away -- and later collide with surrounding material inside the Earth. Their energy of motion is converted to heat -- to create Earth's primary heat source. Without radioactive decay, Earth would have fewer volcanoes or earthquakes -- less shifting of land plates and building of vast mountain ranges.

JB: The heat energy produced by Earth is enormous, but it's 5000 times less than what Earth receives from the sun. The sun's heat drives the weather and ultimately causes erosion.

DB: So while the Earth's heat builds mountains, the sun's heat destroys them. With thanks to the National Science Foundation, we're Block and Byrd for Earth and Sky.

Author(s): Bizy Kubala, Mohan Rao, Marc Airhart, Deborah Byrd

Please let us know what you think!

Saturday, February 26, 2005 • Monday, February 28, 2005

© 2005 Byrd & Block Communications Inc. Permission to use, copy and distribute these materials without fee is hereby granted, provided that the above copyright notice appear in all copies and the materials are not redistributed for profit.

025 Moon and Jupiter: Cloze Test and Crossword Puzzle

2005-02-28T01:59:00.000-08:00

Please click here for a Cloze Test on Moon and Jupiter. If you send me an email, I'll be quite happy to send you a crossword about this topic. Please put '025 Moon and Jupiter: Crossword Puzzle' in the Subject line.

024 Moon and Jupiter: HotSpots and Advanced VocabBox

2005-02-28T00:19:00.000-08:00

Moon
moon
Jupiter
solar system
Jupiter and its moons
Jovian moons images
Io
Europa
Ganymede
Callisto
orbit with a single hemisphere perpetually aimed toward their parent planet
orbital resonance

023 Moon and Jupiter: HotSpots and Intermediate VocabBox and Glossary and Vocabulary Double-Check

2005-02-27T23:33:00.000-08:00

Moon: the natural satellite of the earth
moon: any natural satellite of a planet
Jupiter: the largest of the planets and the fifth from the sun
fifth planet outward from the sun: the planets are numbered from the sun so the 1st is Mercury and the 5th is Jupiter
solar system: the system containing the sun and the heavenly bodies held in its gravitational field, including the planets [Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto], their moons, the asteroids, and comets
largest planet: Jupiter is the largest of the planets with its diameter 11.2 times the diameter of the Earth, and its mass is 317.9 times the mass of the Earth
Jupiter and its moons: the planet has four large moons and dozens of small ones; altogether there are 60 known moons [in 2005]
heavenly bodies: stars, and planets, and moons, and asteroids, and comets
eastern horizon: the sky in the east where we normally see the sunrise
turns eastward beneath the heavens: we have a feeling that the sky above us is turning in that direction; in reality the earth rotates on its axis
travel westward: we have an illusion that all those heavenly bodies travel westward; in reality the earth rotates on its axis
Jovian moons: the moons of Jupiter; in another expression, 'Jovian planets', Jovian means either of the four giant planets, i. e. Jupiter, Saturn, Uranus, or Neptune
outward from Jupiter: starting from the moon that is closest to the planet towards the one that is the most distanced
Io: the first satellite of Jupiter and the third largest, discovered in 1610 by Galileo
Europa: the fourth largest satellite of Jupiter and the second nearest to the planet, discovered in 1610 by Galileo
Ganymede: the third satellite of Jupiter and the largest in the solar system; it was discovered in 1610 by Galileo
Callisto: the fourth satellite of Jupiter and the second largest, discovered in 1610 by Galileo
orbit with a single hemisphere perpetually aimed toward their parent planet: the same face turns towards the planet all the time
orbital resonance: when two orbiting bodies have periods of revolution that are in a simple integer ratio [i. e. one is exactly same as, or two times, or three times, or four times, etc. higher than the other] so that they exert a regular gravitational influence on each other

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022 Moon and Jupiter: Text and HotSpots

2005-02-27T23:05:00.000-08:00

Moon and Jupiter

Jupiter is the fifth planet outward from the sun and the solar system's largest planet. It shines close to the moon for the next two nights. Jupiter and its moons -- coming up after this -- on Earth and Sky.

Saturday, February 26, 2005

DB: I'm Deborah Byrd.

JB: And I'm Joel Block for Earth and Sky -- Saturday, February 26. The two brightest heavenly bodies in the night sky now -- the moon and the planet Jupiter -- rise above your eastern horizon in mid to late evening tonight. As Earth turns eastward beneath the heavens, the moon and Jupiter will travel westward across your sky. They'll shine close together all night long tonight and tomorrow night.

DB: Jupiter is the largest planet in our solar system, and it has the largest number of known moons -- over 60 at last count. Most of the Jovian moons are small, and you can't see them by looking through amateur telescopes on Earth. But you can see Jupiter's four largest moons fairly easily through a small telescope or even binoculars. In their order outward from Jupiter, these moons are Io, Europa, Ganymede and Callisto.

JB: Io and Europa are about the size of Earth's moon. Ganymede and Callisto are 50 percent bigger in diameter. These four moons -- like Earth's moon and most other moons in our solar system -- orbit with a single hemisphere perpetually aimed toward their parent planet.

DB: What's more, the moons Io, Europa and Ganymede are locked into what is called an orbital resonance with Jupiter. For every single orbit of Ganymede around Jupiter, Europa orbits Jupiter twice and Io orbits Jupiter four times.

JB: That's today's show. We're Block and Byrd for Earth and Sky.
Author(s): Bruce McClure

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Friday, February 25, 2005 • Sunday, February 27, 2005

© 2005 Byrd & Block Communications Inc. Permission to use, copy and distribute these materials without fee is hereby granted, provided that the above copyright notice appear in all copies and the materials are not redistributed for profit.

021 Moon and Jupiter: Sound and Text

2005-02-27T23:01:00.000-08:00

Saturday, February 26, 2005

Click here for LISTENING

Click here for original article MOON AND JUPITER

DB: I'm Deborah Byrd.

JB: And I'm Joel Block for Earth and Sky -- Saturday, February 26. The two brightest heavenly bodies in the night sky now -- the moon and the planet Jupiter -- rise above your eastern horizon in mid to late evening tonight. As Earth turns eastward beneath the heavens, the moon and Jupiter will travel westward across your sky. They'll shine close together all night long tonight and tomorrow night.

DB: Jupiter is the largest planet in our solar system, and it has the largest number of known moons -- over 60 at last count. Most of the Jovian moons are small, and you can't see them by looking through amateur telescopes on Earth. But you can see Jupiter's four largest moons fairly easily through a small telescope or even binoculars. In their order outward from Jupiter, these moons are Io, Europa, Ganymede and Callisto.

JB: Io and Europa are about the size of Earth's moon. Ganymede and Callisto are 50 percent bigger in diameter. These four moons -- like Earth's moon and most other moons in our solar system -- orbit with a single hemisphere perpetually aimed toward their parent planet.

DB: What's more, the moons Io, Europa and Ganymede are locked into what is called an orbital resonance with Jupiter. For every single orbit of Ganymede around Jupiter, Europa orbits Jupiter twice and Io orbits Jupiter four times.

JB: That's today's show. We're Block and Byrd for Earth and Sky.
Author(s): Bruce McClure

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Friday, February 25, 2005 • Sunday, February 27, 2005

020 Twenty-Four Hours: Cloze Test and Crossword Puzzle

2005-02-27T10:46:00.000-08:00

Please click here for a Cloze Test on Twenty-Four Hours. If you send me an email, I'll be quite happy to send you a crossword about this topic. Please put '020 Twenty-Four Hours: Crossword Puzzle' in the Subject line.

019 Twenty-Four Hours: HotSpots and Advanced VocabBox

2005-02-27T01:16:00.000-08:00

early Egyptians
calendar
month
year year # 2
holiday
hour
yearly cycle
Winter Solstice
Spring Equinox
Summer Solstice
Autumnal Equinox
heliacal rising
twilight periods
seasonal hours
Greek astronomers
Hipparchus
Ptolemy
Middle Ages
mechanical clocks mechanical clocks # 2

018 Twenty-Four Hours: HotSpots and Intermediate VocabBox and Glossary and Vocabulary Double-Check

2005-02-27T01:07:00.000-08:00

early Egyptians: people living in Egypt in the Dynastic Period [3000 B.C.E. to 332 B. C. E.], in the Hellenistic Period [332 B. C. E. to 30 B. C. E.], and in part of the Roman and Byzantine Rule [30 B. C. E to 642 C. E]
calendar: a system of determining the beginning, length, and order of years and their devisions
month: one of the twelve divisions of the calendar year; originally the period of time taken by the moon to return to the same longitude after one complete revolution around the earth
holiday: a period in which a break is taken from work or studies for rest, travel, or recreation; originally 'holy day'
hour: a period of time equal to 3600 seconds; 1/24th of a calendar day
B.C.: Before Christ; indicating years numbered back from the supposed year of the birth of Christ
A.D.: Anno Domini; indicating years years numbered from the supposed year of the birth of Christ
C.E.: Common Era; a religiously neutral term for A. D.
B.C.E.: Before Common Era; a religiously neutral term for B. C.
yearly cycle: the yearly cycle can be divided up into four parts by Winter Solstice [shortest day - longest night], Spring Equinox [day and night are of equal length in the Sring], Summer Solstice [longest day - shortest night], and Autumnal Equinox [day and night are of equal length in the Autumn]
heliacal rising: the rising of a celestial object at the same time as the rising of the sun
twilight periods: the soft diffused light occuring when the sun is just below the horizon, esp. following sunset
seasonal hours: it derives from the Medieval idea of dividing the day into twelve equal hours no matter how long the day actually lasts; thus in the summer a seasonal hours will be longer than a standard hour and conversely in the winter it will be shorter
Greek astronomers: a high number of persons ranging from Hipparchus in the second century B.C. to Ptolemy in the second century A.D.
Middle Ages: the period from the fall of the West Roman Empire in A. D. 476 to the fall of Constantinople in 1453
mechanical clocks: mechanisms that replaced the old water clocks by the 13th Century

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017 Twenty-Four Hours: Text and HotSpots

2005-02-26T11:42:00.000-08:00

Twenty-Four Hours

The early Egyptians made a calendar of 365 days. It had 12 months of 30 days --plus five holidays at the end of the year. How our day of 24 hours also came from this calendar -- after this on Earth and Sky.
Friday, February 25, 2005

DB: This is Earth and Sky. A listener wants to know, "Why are there 24 hours in a day?"

JB: Our system of 24 hours comes from Egyptian culture. Around the 30th century B.C., the Egyptians used a calendar in which each month was divided into three periods of 10 days each.

DB: Now consider that all stars move in a yearly cycle, due to Earth's motion around the sun. The first appearance of a star before sunrise -- at the start of its new season of visibility -- is known as its heliacal rising. The Egyptians came to associate the heliacal rising of a particular bright star with each of their 10-day periods over the course of a year. Night came to be associated with 12 stars -- about how many would rise each night during the summer months.

JB: Meanwhile, the Egyptians divided the period from sunrise to sunset into 10 parts. And they added an hour before sunrise and after sunset for twilight periods -- for a total of 24 hours in a day/night period. The length of these original "hours" varied with the seasons. They were called "seasonal" hours. Hours of equal length were introduced by Greek astronomers. But as late as the Middle Ages, when mechanical clocks were coming into use, seasonal hours were still used in everyday life.

DB: For today, that's our show. We're Block and Byrd for Earth and Sky.
Author(s): LeRoy Doggett, Tara Ross, Deborah Byrd

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Thursday, February 24, 2005 • Saturday, February 26, 2005

016 Twenty-Four Hours: Sound and Text

2005-02-26T11:27:00.000-08:00

Click here for LISTENING

Click here for original article TWENTY-FOUR HOURS

DB: This is Earth and Sky. A listener wants to know, "Why are there 24 hours in a day?"

JB: Our system of 24 hours comes from Egyptian culture. Around the 30th century B.C., the Egyptians used a calendar in which each month was divided into three periods of 10 days each.

DB: For today, that's our show. We're Block and Byrd for Earth and Sky.

Author(s): LeRoy Doggett, Tara Ross, Deborah Byrd

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Thursday, February 24, 2005 • Saturday, February 26, 2005

015 Noon and Midnight: Cloze Test and Crossword Puzzle

2005-02-24T05:30:00.000-08:00

Please click here for a Cloze Test on Noon and Midnight. If you send me an email, I'll be quite happy to send you a crossword about this topic. Please put '015 Noon and Midnight: Crossword Puzzle' in the Subject line.

014 Noon and Midnight: HotSpots and Advanced VocabBox

2005-02-24T04:25:00.000-08:00

noon
midnight
a.m.
p.m.
designation the meaning is 'market out', indicated or specified; it comes from the Latin 'designatus' meaning 'marked out'
o'clock
astronomer
meridian

013 Noon and Midnight: HotSpots and Intermediate VocabBox and Glossary and Vocabulary Double-Check

2005-02-24T04:00:00.000-08:00

noon: the middle of the day; 12 o'clock in the daytime or point at which the sun crosses the local meridian
midnight: the middle of the night; 12 o'clock at night
a.m.: short for the Latin 'ante meridiem' which is literally 'before noon'; it is used for the time between midnight and noon
p.m.: short for the Latin 'post meridiem' which is literally 'after noon'; it is used for the time between noon and midnight
designation: indication or specification
o'clock: used after a number from 1 to 12 to indicate the hour of the day or night; it is the abbreviation for 'of the clock'
tonight: the night or evening of this present day; it comes from the Old English 'toniht' where 'to' means 'at' in Modern English and 'niht' stands for 'night'
astronomer: a scientist who studies astronomy, i. e. the individual celestial bodies [excluding the earth] and the universe as a whole
airlines: a system or organization that provides scheduled flights for passengers or cargo
schedule flights: arranging or planning flights into a timetable; to make them part of the regular service rather than being specially chartered
meridian: the great circle on the celestial sphere [this is what we call 'sky'] passing through the north and south celestial poles; the highest point [vertically above the observer] is called 'zenith' [the opposite is called 'nadir']

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012 Noon and Midnight: Text and HotSpots

2005-02-24T03:14:00.000-08:00

Noon and Midnight

We answer a listener's question about noon and midnight -- after this on Earth and Sky.

Thursday, February 24, 2005

JB: This is Earth and Sky. A listener asks, "Do noon and midnight have an a.m./p.m. designation? A friend of mine says that noon is 12 p.m. and midnight is 12 a.m."

DB: Officially, there's no such thing as 12 p.m. or 12 a.m. Noon and midnight aren't defined as either one. You can talk about 12.01 a.m., and you can talk about 12:01 p.m., but 12 o'clock a.m. and 12 o'clock p.m. mean different things to different people -- like you and your friend. So officially 12 a.m. and p.m. have no meaning. It's better to say noon or midnight.

JB: So does tonight's midnight really belong to tonight -- or to tomorrow morning? Astronomers and the military use a system where midnight is 0 hours -- and, in that system tonight's midnight is the first moment of tomorrow. To avoid confusion, airlines always schedule flights for 11:59 p.m. or 12:01 a.m. -- never midnight.

DB: The notion of "time of day" for early people came from watching the sun. Imagine looking at the sun at its highest in the sky. Then draw an imaginary line from north to south, through the sun. That line is called the "meridian" by astronomers.

JB: And that's a.m. and p.m. come from . . . ante meridian, morning, or before the sun reaches the meridian . . .and post meridian, after the sun has passed the meridian and is heading now toward sunset.

DB: For today, that's our show. We're Block and Byrd for Earth and Sky.

Author(s): Tara Ross, Deborah Byrd

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Wednesday, February 23, 2005 • Friday, February 25, 2005

011 Noon and Midnight: Sound and Text

2005-02-24T03:02:00.000-08:00

Noon and Midnight

We answer a listener's question about noon and midnight -- after this on Earth and Sky.

Thursday, February 24, 2005

Click here for LISTENING

Click here for original article NOON AND MIDNIGHT

JB: This is Earth and Sky. A listener asks, "Do noon and midnight have an a.m./p.m. designation? A friend of mine says that noon is 12 p.m. and midnight is 12 a.m."

DB: For today, that's our show. We're Block and Byrd for Earth and Sky.

Author(s): Tara Ross, Deborah Byrd

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Wednesday, February 23, 2005 • Friday, February 25, 2005

010 February Full Moon: Cloze Test and Crossword Puzzle

2005-02-23T02:03:00.000-08:00

Please click here for a Cloze Test on February Full Moon. If you send me an email, I'll be quite happy to send you a crossword about this topic. Please put '010 February Full Moon: Crossword Puzzle' in the Subject line.

009 February Full Moon: HotSpots and Advanced VocabBox

2005-02-23T02:01:00.000-08:00

full moon
crest
phase
constellation
Leo the Lion
cycles of 19 years
Regulus
Heart of the Lion
Algieba
Lion's Mane

008 February Full Moon: HotSpots and Intermediate VocabBox and Glossary and Vocabulary Double-Check

2005-02-23T01:41:00.000-08:00

full moon: one of the four main phases of the moon, occuring when the earth lies between the sun and the moon so that the moon is visible as a fully illuminated disc
crest: come or rise to a high point
phase: any one of the eight sub-phases, i. e. new moon, waxing crescent, 1st quarter, waxing gibbous, full moon, waning gibbous, 3rd quarter, waning crescent
constellation: any one of 88 groups of stars as seen from the earth or from the solar system, many of which were named by the ancient Greeks after animals, objects, or mythological pesons
Leo the Lion: a zodiacal constellation of the Northern hemisphere, lying between Cancer and Virgo, that contains the star Regulus and the radiant of the Leonid meteor shower
cycles of 19 years: If one picks a year that starts with a New Moon and lets the months run in sequence, how many lunar months pass before another year comes that starts on a New Moon? The answer is 235 lunar months - or 19 years. In other words the Full Moon appears on the same day in that year as it did 19 years earlier.
Regulus: the brightest star in the constellation Leo
Heart of the Lion: the star Regulus represents the heart of the lion in the constellation Leo
Algieba: the second brightest star in the constellation Leo
Lion's Mane: the star Algieba represents the mane of the lion in the constellation Leo

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007 February Full Moon: Text and HotSpots

2005-02-23T00:06:00.000-08:00

February Full Moon

A listener asks if the full moon can take place on different dates, depending on your location on the globe. The dates of full moons -- and tonight's full moon -- after this on Earth and Sky.

Wednesday, February 23, 2005

JB: This is Earth and Sky -- Wednesday, February 23. A listener wants to know the exact moment of the February full moon.

DB: Every full moon crests at the same moment for all of us around the globe. But our clocks say different times. If you live in the eastern United States, the moon becomes full tonight at precisely 11:54 p.m. That's only moments before the midnight hour, so for those in eastern North America the full moon falls on February 23 -- but just barely.

JB: For the rest of the U.S., the February full moon also falls on today's date, February 23. Meanwhile, for Europe, Africa, Asia, Australia and New Zealand, your clocks and calendars will say it's after midnight tonight -- on Thursday, February 24 -- when the moon reaches the crest of its full phase. But again, it's just our clocks and calendars that read differently. And full moon happens at the same moment for all of us.

DB: This February full moon shines in front of the stars of the constellation Leo the Lion. In cycles of 19 years, the February full moon always falls on or near this date, and returns to nearly the same spot amidst the stars of Leo. You'll see two fairly bright stars near the moon tonight. One is Regulus, representing the Heart of the Lion in the constellation Leo. The other is Algieba, in the Lion's Mane.

JB: That's our show. For sky charts and more information, visit our web site at earthsky.org. We're Block and Byrd for Earth and Sky.
Author(s): Bruce McClure
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Tuesday, February 22, 2005 • Thursday, February 24, 2005
© 2005 Byrd & Block Communications Inc. Permission to use, copy and distribute these materials without fee is hereby granted, provided that the above copyright notice appear in all copies and the materials are not redistributed for profit.

006 February Full Moon: Sound and Text

2005-02-22T23:39:00.000-08:00

Wednesday, February 23, 2005

Click here for LISTENING

Click here for original article FEBRUARY FULL MOON

JB: This is Earth and Sky -- Wednesday, February 23. A listener wants to know the exact moment of the February full moon.

JB: That's our show. For sky charts and more information, visit our web site at earthsky.org. We're Block and Byrd for Earth and Sky.

Author(s): Bruce McClure
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Want to see the previously mentioned chart? Check out Tonight's Sky -- Full Moon in our Skywatching Center.
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Tuesday, February 22, 2005 • Thursday, February 24, 2005
© 2005 Byrd & Block Communications Inc. Permission to use, copy and distribute these materials without fee is hereby granted, provided that the above copyright notice appear in all copies and the materials are not redistributed for profit.

005 Stem Cell Signals: Cloze Test and Crossword Puzzle

2005-02-22T03:44:00.000-08:00

Please click here for a Cloze Test on Stem Cell Signals. If you send me an email, I'll be quite happy to send you a crossword about this topic. Please put '005 Stem Cell Signals: Crossword Puzzle' in the Subject line.

004 Stem Cell Signals: HotSpots and Advanced VocabBox

2005-02-21T12:15:00.000-08:00

stem cell
stem cell # 2
cancer researcher
cancer researcher # 2
degenerative diseases
Alzheimer's
damaged cells
Memorial Sloan-Kettering Cancer Center in New York
genetic heart defect
embryos
proteins
sending chemical signals
sending chemical signals # 2
sending chemical signals # 3

003 Stem Cell Signals: HotSpots and Intermediate VocabBox and Glossary and Vocabulary Double-Check

2005-02-21T11:03:00.000-08:00

stem cell: the term is used in histology, the study of the tissues of an animal or plant; an undifferentiated cell that gives rise to specialised cells

chance discoveries: first of all let's make the difference between a discovery and an invention; we discover something that has existed before but we did not know about it; we invent something that has never existed before and it is absolutely new; a chance discovery is something that was not among our aims and we have discovered it by good luck while looking for something else

cancer researcher: a scientist who studies abnormal and uncontrolled cell division; the most important fields of cancer research include biochemistry, molecular biology and genetics, biology, biophysics, experimental pathology, immunology [a biological science concerned with the study of immunity], virology [the branch of medicine concerned with the study of viruses and the diseases they cause], clinical pharmacology and chemotherapy, epidemiology [the branch of medical science concerned with the occurence, transmission and control of epidemic diseases], hematology [the branch of medical science concerned with diseases of the blood and blood-forming tissues], host-tumor relationships, immunotherapy, and radiation oncology[the branch of medicine concerned with the study, classification, and treatment of tumors]

degenerative disease: a disease marked by gradual deterioration of organs and cells along with loss of function

Alzheimer's: a disorder of the brain resulting in a progressive decline in intellectual and physical abilities, and eventual senility

damaged cells: cells with DNA damage and failure to perform critical processes

Memorial Sloan-Kettering Cancer Center in New York: a medical center in New York, N.Y.; a complex of a cancer hospital and a cancer research institute

genetic heart defect: a structural problem with the heart present at birth

embryo: the human product of conception up to the end of the second month of pregnancy

proteins: any of a large group of nitrogenous compounds of high molecular weight that are essential constituents of all living organisms

sending chemical signals: cells continuously receive information ('signals') from their environment and from their neighbours through different chemicals; these signals are converted into intracellular 'second messenger signals' which ultimately make the cells respond by, for example, dividing, moving or even dying; deregulated signaling is a hallmark of cancer cells

signaling chemicals: the functional aspects of the signaling chemicals are hormones [chemical substances produced in an endocrine gland and transported in the blood to certain tissues], growth factors [chemical substances present in serum that induce growth in cells], and neurotransmitters [chemicals by which nerve cells communicate with other nerve cells or with muscles]; the chemical aspects of signaling chemicals are lipid soluble ligands [chemical complexes that dissolve in fats], and water soluble ligands [chemical complexes that dissolve in water]

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002 Stem Cell Signals: Text and HotSpots

2005-02-21T10:43:00.000-08:00

Please read the text and try to synthesize the meaning of the HotSpots in context:

Stem Cell Signals

Sometimes scientists make chance discoveries important to unexpected fields of study. We talk with a cancer researcher who made a surprising discovery about stem cells -- next on Earth and Sky.

Tuesday, February 22, 2005

JB: This is Earth and Sky. Last October, scientists announced a surprising discovery about stem cells.

DB: Stem cells in the bodies of animals and people can turn into almost any other kind of cell. Researchers already hoped to treat degenerative diseases such as Alzheimer's by using stem cells to replace damaged cells. The new discovery might yield yet another way to use stem cells.

JB: Robert Benezra is a researcher at the Memorial Sloan-Kettering Cancer Center in New York. He was studying mice that tended to die of a genetic heart defect as embryos. They were missing two proteins that are important for developing a healthy heart. To extend their lives, Benezra injected the mouse embryos with stem cells that had the missing proteins.

Robert Benezra: And it was to our surprise and amazement that when we injected even just a few ... embryonic stem cells, the animals not only survived a little bit longer but they were actually born and running around quite happily.

DB: The stem cells hadn't simply taken over and replaced the defective mouse heart cells. Instead, the stem cells were actually sending chemical signals to the defective cells around them that made the bad cells grow normally.

JB: Benezra now thinks doctors might be able to use the signaling chemicals of stem cells -- rather than stem cells themselves -- to treat degenerative diseases. And that's our show. With thanks to the National Science Foundation we're Block and Byrd for Earth and Sky.

Author(s): Marc Airhart

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Monday, February 21, 2005 • Wednesday, February 23, 2005

001 Stem Cell Signals: Sound and Text

2005-02-21T10:35:00.000-08:00

Stem Cell Signals

Click here for LISTENING

Click here for original article STEM CELL SIGNALS

Sometimes scientists make chance discoveries important to unexpected fields of study. We talk with a cancer researcher who made a surprising discovery about stem cells -- next on Earth and Sky.

Tuesday, February 22, 2005

JB: This is Earth and Sky. Last October, scientists announced a surprising discovery about stem cells.

Author(s): Marc Airhart

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Monday, February 21, 2005 • Wednesday, February 23, 2005