Questions and Answers
How was the universe made ?
Many scientists believe that the universe is the result of an explosion called the Big Bang, which occurred about 14 billion years ago.
What was the Big Bang ?
The Big Bang was an explosion of all the matter in the Universe, which was squashed into a tiny area at more than 10 billion degrees C. The matter exploded so quickly that within the hundredth of a second, the universe was as big as the sun ! It carried on growing.
Is there anything left of the big bang ?
Scientists have found that the average temp. of the universe is 3 Degrees C above absolute zero, which is the coldest temp. possible. This heat could come from the big bang continuing to slow down.
Is the universe still getting bigger ?
Yes scientists have discovered that matter and groups of stars are still moving further away from each other. However, they are now moving much more slowly that just after the big bang.
Which is the biggest galaxy ?
The Andromeda galaxy is the biggest galaxy of those near the milky way. On a clear night, all you can see of this galaxy is small fuzzy blob, but it has twice as many stars as milky way - perhaps as many as 200 billions. There may be galaxies even bigger than Andromeda.
When the galaxies discovered ?
The first astronomers called misty patches in the sky nebulae which means mist. It was not until early this century that it was found that many of these mysterious nebulae were actually distant galaxies.
What is the centre of the milky way ?
Scientists have discovered that there is a huge amount of gas at the centre of our galaxy. Some experts think that this may be caused by a enormous, swirling black hole which is slowly sucking.
( Fact ....)
There are millions of spiral galaxies in the universe. These galaxies contains many young stars.
How hot is the Sun ?
The Sun is very hot indeed ! Its surface is 8,000 Degrees C and the temp. at the centre measures 14 million degrees C.
Is the Sun moving ?
Yes, all the planets in our Solar System orbit the sun and in turn our solar system orbits the centre of our galaxy, the Milky Way. It takes about 225 million years or one cosmic year for the sun and nine to travel around the milky way once.
When was the last time a large meteor hit earth ?
The last time this happened was in 1908 in a remote area of Siberia, russia. Great are as of trees were knocked down by the blast.
Which is the biggest asteroid in our solar system ?
Asteroids are bigger than meteors and are like small planets. The largest asteroid in our solar system is ceres, which is over 1000 km wide.
Can we tell the time by stars ?
Yes, Earth spins around once every 24 hours. During the night, stars appears to move across the sky. It is possible to tell the time when their changing positions are measured. Before clocks, stars were an important way of telling the time at night.
Can we measure a star's brightness ?
Yes, a star's brightness is called its magnitude. A star of magnitude 0 is very bright. Stars of magnitude 5 are only just visible. Really bright stars have minus magnitudes. Sirius the brightest star in the sky, has a magnitude of - 1.5.
How did sailors use the stars to find their way at night ?
If we live in the northern hemisphere, one star seems to stay still. This is called the pole star as it is almost directly over the north pole. Sailors knew that its position showed the north, so they could then work out in which direction to sail.