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:
70,000,000,000,000,000,000,000
There are more stars
in the universe than there are grains of sand on all of Earth's
beaches. Multiply
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!
When telescopes
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
a Galaxy?
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
structure.
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
miles/hr.
Stars twinkle
because the light we see coming from the stars travels through the
atmosphere around the earth and there is turbulence in the Earth's
atmosphere.
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.
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
reaches us.
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!
Ever wonder how our planet Earth stacks up against the other planets
in our solar system?
The planets
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).
Feeling smaller?
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
each year.
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
Diamonds.
