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Outer Space
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As many people, I'm mesmorized by the sheer size and scope of the
universe. On this page, visitors will explore facts and information, of which many readers were probably not aware.
I sincerely hope visitors enjoy reading this page as much as I've enjoyed researching the data.
PAGE CONTENTS;
Miscellaneous Tidbits
12-Planet Solar System
The Universe
Stars
Extoplanets
Life and Death of a Big Star
Miscellaneous Tidbits
If an object has no molecules,
the concept of temperature is meaningless. That's why it's technically incorrect to speak of the "cold of outer
space" space has no temperature, and is known as a "temperature sink," meaning it drains heat out of objects.
If one were to capture and bottle a comet's 10,000-mile vapor trail, the amount of vapor actually present in the
bottle would take up less than 1 cubic inch of space. The nucleus of Halley's comet is a peanut-shaped object, weighingabout
100,000 million tons, and measuring about 9 miles by 5 miles. Quasars are amazingly bright objects. A quasar generates 100 times as much light as the whole of our galaxy in a
space not much larger than our solar system.
A galaxy of typical size, about 100 billion suns, produces less energy than a single quasar. A car traveling
at a constant speed of 60 miles per hour would take longer than 48 million years to reach the nearest star (other than our
Sun), Proxima Centauri. This is about 685,000 average human lifetimes.
The star Alpha Herculis is 25 times larger than
the circumference described by Earth's revolution around the Sun. This means that 25 diameters of our solar system orbit
would have to be placed end to end to equal the diameter of the star.
The star Antares is 60,000 times larger than our
Sun. If our Sun were the size of a softball, the star Antares would be as large as a house.
The star known
as LP 327-186, a so-called white dwarf, is smaller than the state of Texas, yet so dense, that if a cubic inch of it were
brought to Earth, it would weigh more than 1.5 million tons. The star Sirius B is so dense, a handful of it weighs about one million pounds.
If a baseball-sized piece of a supernova star (known to astronomers as a pulsar) were brought to Earth, it would
weigh more than the Empire State building.
A neutron star is the strongest magnet in the universe. The magnetic field of a
neutron star is a million million times stronger than Earth's magnetism.
How quickly can a white dwarf form?
Pretty quickly, cosmically speaking - It takes 100,000 years for a red giant to change into a white dwarf. By astronomical
standards, this is practically instantaneous, a mere one-thousandth of the star's life.
Why can't we explore a neutron star first hand?
Because they're super-dense. If an astronaut tried
to land on a neutron star, he or she would be crushed by the extremely strong force of gravity, and squashed into a thin layer
less than one atom thick. This is because neutron stars are actually the collapsed cores of massive stars, packing roughly
the mass of our Sun into a region the size of a city.
A galaxy of typical size, about 100 billion suns,
produces less energy than a single quasar.d
of light is estimated to be 186,000 miles per second. A light-year is how far light travels in one year, which is about
5.9 trillion miles. If an object has no molecules, the concept
of temperature is meaningless. That's why it's technically incorrect to speak of the "cold of outer space"
— space has no temperature, and is known as a "temperature sink," meaning it drains heat out of things. How is fire different in space?
On Earth, gravity determines how the flame
burns. All the hot gases in the flame are much hotter (and less dense) than the surrounding air, so they move upward toward
lower pressure. This is why fire typically spreads upward, and it's also why flames are always "pointed" at
the top. If you were to light a fire in a microgravity environment, say onboard the space shuttle, it would form a sphere.
What would happen if you were in space without
a spacesuit?
Outer space is an extremely hostile place. If you were to step outside a spacecraft or onto a world with
little or no atmosphere and you were not wearing a spacesuit, the following things would happen: You would become unconscious
within 15 seconds because there is no oxygen; Your blood and body fluids would "boil" and then freeze because there
is little or no air pressure; Your tissues (skin, heart, other internal organs) would expand because of the boiling fluids;
You would face extreme changes in temperature (sunlight: 248 degrees Fahrenheit / 120 degrees Celsius, shade: -148 F / -100
C); You would be exposed to various types of radiation, such as cosmic rays, and charged particles emitted from the sun (solar
wind); You could be hit by small particles of dust or rock that move at high speeds (micrometeoroids) or orbiting debris from
satellites or spacecraft.
12-Planet Solar System
by Steve Sampson
Friends, our solar system has 12 planets,
not nine as you've been told all your life. Or so says a committee of experts appointed by the International Astronomical
Union (IAU), the folks who officially keep track of celestial bodies.
The IAU asked its committee to come up
with an answer to the question "what is a planet?" Surprisingly, there's never been an official scientific definition. As
one astronomer has lamented, "It's something of an embarrassment. . . . We live on a planet; it would be nice to know what
that was."
Now, we will--assuming the IAU's members
vote to approve the committee's recommended definition at a meeting in Prague next week. So, what does the new definition
say? And what might a new map of the solar system look like?
According to the new definition, a planet
is any celestial body that meets three criteria:
- It orbits a star.
- It's neither a star nor "a satellite
of a planet" (a moon).
- It's round. More technically, it "has
sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round)
shape."
With this definition, the debate over
whether Pluto's planetary license should be revoked ends. Tiny Pluto gets to be a planet after all. But so does Ceres, the
largest asteroid in the asteroid belt between Mars and Jupiter. It's promoted from "largest asteroid" to "smallest planet"
(or, more accurately, restored, since astronomers counted Ceres as a planet when they found it in 1801). Just 590 miles (950
km) wide, Ceres is less than half Pluto's width.
Along with Ceres, two other known celestial
bodies would immediately become planets. One is the frigid, faraway object officially known as 2003 UB313, nicknamed Xena.
At least as big as Pluto--and three times more distant--Xena's discovery helped push astronomers to define "planet."
The other is Charon, currently known
as Pluto's main moon (Pluto has two other tiny moons, just discovered). Why should Charon count as a planet when our moon
doesn't? Because--at more than half Pluto's size--Charon isn't really a satellite of Pluto. Instead, Pluto and Charon continually
orbit each other. Under the new proposal, Pluto and Charon would count as a "double planet."
Pluto, Charon, and 2003 UB313 would also
be part of a new class of planets called "plutons," which the proposal differentiates from the eight "classical planets."
Like Pluto, the plutons take centuries to circle the sun, and their orbits are elongated and tilted compared with those of
the classical planets. Scientists expect to find a lot more plutons in the years to come--perhaps dozens more.
It all sounds like radical change. But
bear in mind that it's mainly a matter of nomenclature. On a journey out from the sun, you'll still find the following in
our little solar system:
- Four "terrestrial" planets: Mercury,
Venus, Earth, and Mars. These planets are made mostly of rock, they have solid surfaces, and they don't have rings.
- An asteroid belt beyond Mars and
before Jupiter--though on your way through it, you probably won't see a single asteroid. It's far less crowded than you may
think. By far the biggest body is Ceres. It accounts for about a third of the entire mass of the asteroid belt.
- Four gas giants or "Jovian" planets:
Jupiter, Saturn, Uranus, and Neptune. These are big, they're made mostly of gas, and they have rings.
- Pluto, Charon, and a growing number of
other "trans-Neptunian objects." These bodies are distant, cold, and to blame for our changing conceptions of "planet."
Astronomers didn't discover Pluto until
1930. They didn't discover Charon until 1978. And they didn't discover another "trans-Neptunian object" until 1992. Since
then, they've discovered hundreds of them--some as big, or bigger, than Pluto. Whether we wind up calling these objects "planets,"
"plutons," or something else entirely, they're clearly part of a new astronomical frontier--and we're witnessing its birth.
Steve Sampson
August 18, 2006
Copright 2006, KnowledgeNews. All rights reserved.
THE UNIVERSE
The universe is about 15,000 million years old. Put another way, if
the years flashed by at a rate of one each second, the universe would already be nearly 47 years old.
When the Big Bang occurred, some 15 billion years ago, the Universe consisted
of matter and antimatter. Difficult as it might be to believe, most of the matter and antimatter annihilated each other. The
little bit of matter left over makes up everything in Universe today, while most -- but not all -- of the antimatter that
remained seems to have vanished. Some of it has found a useful life in medical procedures, such as in Positron Emission Tomography,
PET, scanners. Scientists at Los Alamos National Laboratory believe other forms of the stuff might be useful, too. First they
must manufacture it but the trick is to avoid annihilating the antimatter when it interacts with matter. So laboratory physicist
Michael Holzschieter will employ a low-tech solution: he will manufacture atoms of antihydrogen and filter them through about
a nickel's worth of aluminum foil. The foil, Holzschieter believes, will slow down the annihilation process enough to let
him capture and study the antihydrogen.
How do we know the universe is expanding?
Astronomers see
countless galaxies for billions of light years in every direction. The farther away a galaxy is, the faster it moves away
from us. The whole universe is expanding. How do we know? When an object moves away from an observer, the light from that
object changes color, similar to the way a train whistle changes pitch if the train is moving away. This "Doppler shift" causes
the light of receding galaxies to stretch out, becoming more reddish. Measuring this "red shift," astronomers can tell how
fast each galaxy is receding. If the universe is currently expanding, it makes sense that at one time it was much smaller.
The "Big Bang" theory, which describes how the universe might have started in a stupendous explosion, is one possible explanation
of how the universe began.
The most distant known object in the Universe is a galaxy 13.6 billion light years
away, according to a New Scientist report. The light from the galaxy was probably emitted when the Universe was just 900 million
years old. "This galaxy is forming stars at a time speculated to be in the 'Dark Ages' of the Universe when galaxies began
to turn on," said Esther Hu at the University of Hawaii, who led the team. Telescopes have previously recorded quasars (extremely
bright objects powered by black holes) at a distance of 13 billion light years. But to see the fainter galaxy, they had to
use the gravity of an intervening object as a lens to magnify the light. The researchers hope to use the technique to see
some of the galaxies that experienced the first star formation 14 billion years ago.
Longest Distance
The longest unit of distance is the "Hubble
Length," which is the radius of the observable universe. That's about 10-15 billion light years. This unit of length was named
after Edwin Hubble, an astronomer who discovered that the universe appears to be expanding. A light year is the distance light
travels in a year, which is about 5,866,000,000,000 miles, or 5.9 trillion miles. The Hubble Length is (minimum) ten billion
times that, or 59 sextillion miles! (American definitions for billion, trillion, and sextillion are being used here.) Cosmologists
(scientists who study the history of the universe) suspect that the universe may go on far beyond the edge of what we can
see. No one knows just how big it really is.
BLACK HOLES' AREN'T HOLES AT ALL
Researchers from the U.S.
Department of Energy's Los Alamos National Laboratory and the University of South Carolina have provided a hypothesis that
"black holes" in space are not holes at all, but instead are more akin to bubbles. Emil Mottola of Los Alamos' Theoretical
Division presented the new explanation for black holes at the American Physical Society annual meeting in Albuquerque, N.M.
Pawel Mazur of the University of South Carolina is his co-author. The researchers' explanation redefines black holes not as
"holes" in space where matter and light inexplicably disappear into another dimension, but rather as spherical voids surrounded
by an extremely durable form of matter never before experienced on Earth. Mazur and Mottola call the extraordinary objects
Gravastars. Based on earlier-held astrophysical explanations, black holes form in space when stars reach the end of their
lives and collapse in on themselves. Mottola and Pawel suggest that while some degree of collapsing does take place in a dying
star, the collapse proceeds only to a certain point. Then the intense gravity of the dying star transforms the star's matter
into an entirely new phase.
It is estimated by scientists that the universe contains .0000000000000000000000000000001
grams of matter per cubic centimeter of space. It is also estimated that the universe is 35 billion light years in size, or
210,000,000,000,000,000,000,000 miles.
It is estimated that within the entire universe there are more than a trillion
galaxies.
STARS
Can you count all the stars in the sky?
Only
if you're really fast and live to be very, very old - If you attempted to count the stars in a galaxy at a rate of one every
second, it would take around 3,000 years to count them all.
How dense is a neutron star?
A teaspoon
of neutron star material weighs about 110 million tons.
If an astronaut tried to land on a neutron star, he or she would
be crushed by the extremely strong force of gravity and squashed into a thin layer less than one atom thick.
WHAT IS THE IS THE STRONGEST NATURALLY OCCURRING MAGNET?
A
neutron star is the strongest magnet in the universe. The magnetic field of a neutron star is a million million times stronger
than Earth's magnetism.
How dark is the black background between the stars?
Even
the deepest blackness of intergalactic space is not completely dark. Scientists first discovered in 1965 that the darkest
space between the galaxies contains microwaves (low-energy light waves) at a temperature of about three Celsius degrees above
absolute zero. This is called the cosmic microwave background radiation. Because the universe seems to be expanding and cooling,
cosmologists suspect that it was much hotter and denser in the past. The notion that the expansion of the universe started
with a very hot, dense state that subsequently exploded is called the "Big Bang" theory. If true, then the cosmic background
radiation is the cooled light (a kind of echo) of that explosion. By studying the background radiation, scientists hope to
understand more about the early history of the universe.
How big is Betelgeuse?
The giant red star
Betelguese - the red star in the shoulder of the constellation Orion - is 700 million miles across, about 800 times larger
than the Sun. Light takes 1 hour to travel from one side of the giant star to the other.
How much does a pulsar weigh?
If a baseball-sized
piece of a supernova star (known to astronomers as a pulsar) were brought to Earth, it would weigh more than the Empire State
building
How much does a white dwarf weigh?
A white
dwarf has a mass equal to that of the Sun, but a diameter only about that of Earth. A cupful of white dwarf material weighs
about 22 tons, the same as five elephants.
A galaxy of typical size, about 100 billion suns, produces less energy than a
single quasar.
A car traveling at a constant speed of 60 miles per hour would take longer than 48 million years to
reach the nearest star (other than our Sun), Proxima Centauri. This is about 685,000 average human lifetimes.
The star Alpha Herculis is 25 times larger than the circumference described by
Earth's revolution around the Sun. This means that 25 diameters of our solar system orbit would have to be placed end to end
to equal the diameter of the star.
The star Antares is 60,000 times larger than our Sun. If our Sun were the size
of a softball, the star Antares would be as large as a house.
The star known as LP 327-186, a so-called white dwarf, is smaller than the state
of Texas, yet so dense, that if a cubic inch of it were brought to Earth, it would weigh more than 1.5 million tons.
The star Sirius B is so dense, a handful of it weighs about one million pounds.
If a baseball-sized piece of a supernova star (known to astronomers as a pulsar)
were brought to Earth, it would weigh more than the Empire State building.
How quickly can a white dwarf form?
Pretty
quickly, cosmically speaking - It takes 100,000 years for a red giant to change into a white dwarf. By astronomical standards,
this is practically instantaneous, a mere one-thousandth of the star's life.
Why can't we explore a neutron star first hand?
Because they're super-dense. If an astronaut tried to land on a neutron star, he or she would be crushed
by the extremely strong force of gravity, and squashed into a thin layer less than one atom thick. This is because neutron
stars are actually the collapsed cores of massive stars, packing roughly the mass of our Sun into a region the size of a city
A car traveling at a constant speed of 60 miles per hour would take longer than
48 million years to reach the nearest star (other than our Sun), Proxima Centauri. This is about 685,000 average human lifetimes
It takes 100,000 years for a red giant to change into a white dwarf. By astronomical
standards, this is practically instantaneous, a mere one-thousandth of the star's life.
A galaxy of typical size, about 100 billion suns, produces less energy than a
single quasar.
Extoplanets
The hunt for exoplanets--worlds that orbit stars other than our
sun--is on, and the hunters have had a good year. A top team of astronomers announced that they've found 28 such planets
in the past 12 months alone.
Until 15 years ago, there were no confirmed exoplanet detections.
Now there are nearly 250 of them. And the planet hunters are just getting started. "We're just now getting to the point where,
if we were observing our own solar system from afar, we would be seeing Jupiter," said one researcher.
Jupiter is a gaseous giant. It's about 2.5 times more massive
than all of the other planets in our solar system combined--and about 318 times more massive than Earth alone.
Most of the exoplanets spotted so far are probably big balls of
gas, too. But as technologies improve, astronomers expect to detect many smaller, rockier planets--including some that are
lukewarm and wet, like Earth.
Spotting any exoplanet is no mean feat. They're almost always
too far away--and too washed out by light from the stars they orbit--to be seen directly. Astronomers generally search for
them by looking for "wobbles" they cause in the light coming from their parent stars.
Still, they've already found a few that they think are far Earthier
than Jupiter. One, called Gliese 436 b, appears to be a Neptune-sized planet, with a rocky core covered in water (albeit water
compressed into solid form). Another, called Gliese 581 c, recently made news for being perhaps the most Earthlike place in
the known universe (other than Earth).
Granted, the known universe is a lot smaller than the actual one.
Planet hunters estimate that 10 percent of the Milky Way's 100 billion (or more) stars have planetary systems, and that 30
percent of the stars with planetary systems have more than one planet. That means that the 250 exoplanets detected so far
are just a drop in the galactic bucket.
And that's just the Milky Way bucket. Some estimates say a universal
census would count at least 100 billion galaxies. Those billions of galaxies include billions of billions of stars. Even if
only a fraction of those have planetary systems, the number of exoplanets is downright astronomical. Clearly, the effort to
explore strange new worlds has only just begun.
--Steve Sampson
KnowledgeNews is brought to you by Every Learner, Inc., an
independent small business dedicated to supporting lifelong learners. Copyright © 2007, Every Learner, Inc. All rights reserved.
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The
Hot Life and Violent Death of a Big Star
Like humans,
stars are born through contractions--though the contractions here are not of muscle, but of massive clouds of gas and dust
in interstellar space. Every now and then, such a cloud accumulates enough matter for gravitational forces to pull it together
even more. A protostar is born, and gets hot. When the temperature near its center hits about 1,800,000° Fahrenheit (1,000,000°
Celsius), nuclear reactions kick in.
Newborn stars are made mostly of hydrogen. At their cores, they "burn"
hydrogen and generate helium. Of course, they don't use matches or flames. The burning at a young star's heart is a nuclear
fusion reaction, in which four hydrogen atoms fuse to produce a single helium atom. The mass of that helium atom is less than
the combined mass of the four hydrogen atoms, and the leftover mass is released as energy.
The release of that energy drives the heat inside the star way up--in
some cases to hundreds of millions (even billions) of degrees. Pressure inside the star increases enough to counter the gravitational
forces still trying to contract it. At the same time, heat pours from the star's core toward its cooler surface, and from
there into space. Presto: a relatively stable star is burning bright.
Stars survive a long time by human measures, but eventually they all
run out of gas, literally. And those that live larger burn out quicker. A relatively small star--like our sun--might burn
for 10 billion years, and then linger for eons as a cosmic cinder called a "white dwarf." A star 10 times as massive might
live just 10 million years, and then go out with a bang.
When a star's core runs out of hydrogen to burn, it begins to contract
again. The core's temperature increases until the helium made earlier ignites. Now a helium fusion reaction produces carbon
and oxygen in the star's core, while hydrogen fusion fires up in a thin shell around it. The star generates far more energy
than before, and puffs up accordingly. If the star started out modest, it grows into a red giant. If it started out big, it
becomes a supergiant.
Smaller stars' nuclear careers generally end with the burning of core
helium. But big stars start burning the carbon and oxygen fused in the helium reaction, too. They go on to produce elements
like neon, magnesium, sulfur, and silicon. Then they burn the silicon to produce iron. Such stars wind up layered like onions--with
a central core of iron, surrounded by layers of burning silicon, sulfur, oxygen, carbon, helium, and hydrogen.
After taking several million years to grow up, a supergiant builds
its iron core in about a day. At its peak, the iron core is around two-thirds the size of the Earth but contains more mass
than the sun. It's also caught in an enormous gravitational crunch. The star's core no longer generates energy to counteract
the forces of contraction--to fuse iron requires energy input rather than leading to energy release--so it can't hold out
for long.
When it goes, it goes fast. In less than a second, the core collapses
from a 5,000-mile-wide sphere into a 12-mile-wide one. The sudden crash releases a huge amount of energy--100 times the energy
our sun will produce in its entire 10-billion-year life. Tiny particles called neutrinos carry most of that energy off into
space. The rest races out through the star's layers in a supercharged shockwave.
The resulting explosion blasts the star's gaseous shell into space
at speeds exceeding 10 million miles per hour. For a few weeks, this "supernova" burns brighter than a billion suns. And for
millennia to come, the former star's gaseous shell plows into the interstellar medium. Meanwhile, the star's collapsed iron
core carries on as a neutron star--or, in some cases, becomes a black hole. In the cosmos, it seems, big stars burn out and
fade away.
Steve Sampson
Copyright
2005, KnowledgeNews. All rights reserved. |
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