Science says that the universe was created in a Big
Bang 13.7 billion years ago.
One of the most
persistently asked questions has been: How was the universe created?
Many once believed that the universe had no beginning or end and was
truly infinite. Through the inception of the Big Bang theory
however, no longer could the universe be considered infinite. The
universe was forced to take on the properties of a finite
phenomenon, possessing a history and a beginning.
About 15 billion
years ago a tremendous explosion started the expansion of the
universe. This explosion is known as the Big Bang. At the point of
this event all of the matter and energy of space was contained at
one point. What existed prior to this event is completely unknown
and is a matter of pure speculation. This occurrence was not a
conventional explosion but rather an event filling all of space with
all of the particles of the embryonic universe rushing away from
each other. The Big Bang actually consisted of an explosion of space
within itself unlike an explosion of a bomb were fragments are
thrown outward. The galaxies were not all clumped together, but
rather the Big Bang lay the foundations for the universe.
The origin of the
Big Bang theory can be credited to Edwin Hubble. Hubble made the
observation that the universe is continuously expanding. He
discovered that a galaxy's velocity is proportional to its distance.
Galaxies that are twice as far from us move twice as fast. Another
consequence is that the universe is expanding in every direction.
This observation means that it has taken every galaxy the same
amount of time to move from a common starting position to its
current position. Just as the Big Bang provided for the foundation
of the universe, Hubble's observations provided for the foundation
of the Big Bang theory.
The universe is at least 156 billion light-years wide.
Astronomers estimate that there are 70 sextillion stars in the
visible universe, or some 70 thousand million million million.
That's a 7 followed by 22 zeros, or:
There are more stars
in the universe than there are grains of sand on all of Earth's
our grains of sand by 10 and you still won't even come close to the
actual number of stars in our universe.
There are 100,000
times as many stars in the universe as sounds and words ever uttered
by all humans who have ever lived.
The Hubble Space
Telescope (HST) site estimates there are hundreds of billions of
galaxies in the universe. A recent German super-computer simulation
estimates that the number may be as high as 500 billion!
are pointed at a galaxy that is, say, 10 billion light-years away,
the light it detects left that galaxy 10 billion years ago.
Light from the sun takes 8 minutes to reach you, thus you see the
sun as it was 8 minutes ago. It might have blown up 4 minutes ago
and you wouldn't know about it!
The disk of our Milky Way galaxy
is about 100,000 light years in diameter (one light year is nearly 6
trillion miles), but only about 1000 light years thick. If you
could travel across our Galaxy from one side to the other at the
speed of light
(186,000 miles per second), it would take 100,000 years to make the trip.
Our Galaxy is
estimated to contain at least
200 billion stars and possibly up to 400 billion stars. If each star in our galaxy were
the size of a grain of salt it would make a pile four feet
across and four feet high.
If there is
intelligent life for one in every million stars, our galaxy has over
200,000 extraterrestrial civilizations.
So what exactly is
Galaxies are large
systems of stars, dust and gas bound together by gravitational
force. Most galaxies are tens of thousands of
light years in diameter, and contain billions of stars. Galaxies
come in three primary shapes; spiral galaxies are thin disks, with
spiral arms surrounding a
central hub; elliptical galaxies are uniform, oval-shaped
agglomerations; and irregular galaxies have little or no definite
When you watch the
night sky, you notice that all of the objects in the night sky
appear to be moving across the sky very slowly from east to west.
The apparent speed and motion of everything is due to the rotational
speed of the earth. The earth rotates on its axis at about 1,000
because the light we see coming from the stars travels through the
atmosphere around the earth and there is turbulence in the Earth's
How long would it
take to travel to the nearest star?
Using the kinds of
propulsion systems we have, and taking advantage of a 'gravitational
slingshot' from Jupiter, we could probably get up to 150,000 miles per
hour. The nearest star is Proxima Centauri at a distance of 4.2 light
years. At a speed of 150,000 miles per hour from a passive slingshot
maneuver, it would take about 17,900 years to reach this star.
Super-fast space travel
would kill you in minutes.
thinks it would be cool to travel at the speed of light, which is why
scientists devote their lives to working out if it would be
possible and NASA is trying to develop its own warp drive. But it turns
out super-fast space travel would be fatal.
paper published in Natural Science brings some boring common sense to
the speed-of-light-travel table. In order to travel huge distances,
people need to travel close to the speed of light. In so doing,
travelers cover extremely large distances very quickly and, thanks to
the quirks of relativity, would feel like it took mere minutes because
of an effect known as time dilation, which squashes perceived time.
traveling close to the speed of light brings about other effects,
too. In Natural Science, Edelstein and Edelstein point out that hydrogen
in any craft cable of traveling at the speed of light would also
prevent it from traveling at the speed of light. They explain:
Unfortunately, as spaceship velocities approach the speed of light,
interstellar hydrogen H, although only present at a density of
approximately 1.8 atoms/cm3, turns into intense radiation that would
quickly kill passengers and destroy electronic instrumentation. In
addition, the energy loss of ionizing radiation passing through the
ship's hull represents an increasing heat load that necessitates large
expenditures of energy to cool the ship.
words, travel close to the speed of light and you'll be bombarded with
so much radiation that you kick the bucket. The knock-on effect is that
even if it's possible to create a craft capable of traveling close the
speed of light, it wouldn't be able to transport people.
there's a natural speed limit imposed by safe levels of radiation due to
hydrogen, which means humans couldn't travel faster than half the speed
of light unless they were willing to die almost immediately.
Only 55% of all
Americans know that the Sun is a star.
Q. Why does the moon fit almost exactly
over the sun during an eclipse?
A. The Sun
is roughly 400 times bigger than the Moon and it is 400 times
The sun is over
300,000 times heavier than earth. If our sun were
the size of the dot over this letter "i", the nearest star would be
the same sized dot but 10 miles away.
Every square yard
of the sun's surface sends out energy equal to the power of 700
automobiles. Only about one two-billionth of this energy actually
If a piece of the sun
the size of a pinhead were to be placed on Earth, you could not safely
stand within 90 miles of it!
A neutron star has
such density that a teaspoonful of its matter would weigh more than
all the people on Earth.
Ever wonder how our planet Earth stacks up against the other planets
in our solar system?
compared to the size of our Sun:
Our Sun compared
to other well known Suns beyond our Solar System:
And some real giants:
Antares is the 15th brightest star in the sky. It is more than 1000
light years away.
The pistol star might be the most luminous star
known, producing 4 million times as much power as our
Cephei is so huge, that if we replaced our own sun with it, it would
occupy a space that would extend way past Jupiterís orbit.
largest known star known to man is VY Canis Majoris, a red hypergiant
star located about 5,000 light-years from Earth.
It is so big that it would take over 7,000,000,000 (7 Billion) Suns or
7,000,000,000,000,000 (7 Quadrillion) Earths to fill VY Canis Majoris.
According to some
estimates, approximately 19,000 meteorites weighing about 3.5 ounces
each shower the Earth every day, but only about 10 are recovered
The star "Lucy" in
constellation Centaurus is actually a huge cosmic diamond of 10
billion trillion trillion carats. The cosmic diamond is a chunk of
crystallized carbon, 2,500 miles across, some 50 light-years from
the Earth in the constellation Centaurus. Astronomers have decided
to call the star "Lucy" after the Beatles song, Lucy in the Sky with
The Kuiper Belt
the orbit of Neptune lies the Kuiper belt. It extends
outward an additional three billion kilometers away from
the Sun. The belt contains different-sized lumps of icy
mixtures. These lumps are called Kuiper belt objects.
The biggest are called minor planets or dwarf planets.
The Kuiper belt may have formed when the gravity of the
young planet Jupiter hurled the objects out to where
they are now. The Kuiper belt is named after Gerard
Kuiper (rhymes with "viper"), one of several astronomers
who hypothesized about a field of small objects beyond
Neptune. Since the Kuiper Belt was discovered in 1992,
the number of known Kuiper belt objects (KBOs) has
increased to over a thousand, and more than 70,000 KBOs
over 100 km (62 mi) in diameter are believed to exist
Among the Kuiper Belt
objects is Eris, is the largest known dwarf planet in the Solar
System and the ninth-largest body known to orbit the Sun directly. It is
approximately 2,500 kilometers in diameter and 27% more massive than
Pluto. Originally nicknamed Xena by its discoverers, this
dwarf planet, discovered in 2005, has been officially named Eris
by the International Astronomical Union. The name was proposed by Mike
Brown, a member of the team that made its discovery, and the name was
accepted by the committee.
Magnifying The Universe
This interactive infographic accurately
illustrates the scale of over 100 items within the observable universe
ranging from galaxies to insects, nebulae and stars to molecules and
atoms. Numerous hot points along the zoom slider allow for direct access
to planets, animals, the hydrogen atom and more. As you scroll, a handy
dial spins to show you your present magnification level.
While other sites have tried to magnify
the universe, no one else has done so with real photographs and 3D
renderings. To fully capture the awe of the vastly different sizes of
the Pillars of Creation, Andromeda, the sun, elephants and HIV, you
really need to see images, not just illustrations of these items.
Stunningly enough, the Cat's Eye Nebula is surprising similar to coated
vesicles, showing that even though the nebula is more than
40,000,000,000,000,000,000,000 times larger, many things are similar in
Each time you zoom in a depth, you're
magnifying the universe 10x ... and every time you zoom out, the bigger
objects are 1/10th of their prior size. If you zoom from the biggest
object, The Observable Universe (8.8 x 10E26 ... or
880,000,000,000,000,000,000,000,000m across), all the way down to the
hydrogen atom's proton nucleus (1.7 x 10E-15 ... or 0.0000000000000017m
across), you will have zoomed in over
100,000,000,000,000,000,000,000,000,000,000,000,000,000x! Our universe
really is immensely massive and surprisingly small.
(Click icon in upper-right of
graphic for full screen view.)
The International Space Station (ISS) is a habitable artificial
satellite in low Earth orbit. It follows the Salyut, Almaz, Skylab and Mir stations
as the ninth space station to be inhabited. The ISS is a modular
structure whose first component was launched in 1998. Now the largest
artificial body in orbit, it can often be seen at the appropriate time
with the naked eye from Earth. The ISS consists of pressurized modules,
external trusses, solar arrays and other components. ISS components have
been launched by American Space Shuttles as well as Russian Proton
and Soyuz rockets. Budget constraints led to the merger of three space
station projects with the Japanese Kibō module and Canadian robotics. In
1993 the partially built components for a Soviet/Russian space
station Mir-2, the proposed American Freedom, and the proposed
European Columbus merged into a single multinational program.
The ISS serves as a microgravity and space environment research
laboratory in which crew members conduct experiments in biology, human
biology, physics, astronomy, meteorology and other fields. The station
is suited for the testing of spacecraft systems and equipment required
for missions to the Moon and Mars.
The station has been continuously occupied for 12 years and 136 days,
having exceeded the previous record of almost 10 years (or 3,634 days)
held by Mir, in 2010. The station is serviced by
Soyuz spacecraft, Progress spacecraft, the Automated Transfer Vehicle,
the H-II Transfer Vehicle, and the Dragon spacecraft. It has been
visited by astronauts and cosmonauts from 15 different nations.
The ISS program is a joint project between five participating space
agencies: NASA, the Russian Federal Space Agency, JAXA, ESA, and CSA.
The ownership and use of the space station is established by
intergovernmental treaties and agreements. The station is divided into
two sections, the Russian orbital segment (ROS) and the United States
orbital segment (USOS), which is shared by many nations. The ISS
is maintained at an orbital altitude of between 330 km (205 mi) and
410 km (255 mi). It completes 15.7 orbits per day. The ISS is funded
until 2020, and may operate until 2028. The Russian Federal Space
Agency (RSA/RKA) has proposed using ISS to commission modules for a new
space station, called OPSEK, before the remainder of the ISS is