Q: WHAT IS SPACE?
A: It is the endless vacuum in which the planets, stars, galaxies etc. are placed.
Q: WHAT IS A STAR?
A: It is a celestial body which emits its own light.
Q: WHAT IS A PLANET?
A: It is a celestial body which does not emit its own light usually made of rock or gases. They orbit around stars.
Q: WHAT ARE ASTEROIDS AND COMETS?
A: They are pieces of rock and ice which orbit around stars.
Q: WHAT ARE RED GIANTS AND RED SUPER GIANTS?
A: They are stars at the end of their lives. A middle life star swells up to form a Red Giant. After some time the star may explode. But if it is lucky it will continue to swell up to form a Red Super Giant. After some time there will be a greater explosion and the star would form a Black Hole.
Q: WHAT IS A BLACK HOLE?
A: When stars 8 times the mass of the Sun are at the end of their lives, they collapse under their own gravity. The star shrinks till it forms a single point or a singularity in space; its mass is called a black hole and its boundary is called the event horizon. Light is a particle as well as a wave so it can not escape a black hole’s strong and powerful gravity.
It may be possible to travel in time near black holes, especially to the past.
People thought that black holes were dark but now we know that they emit a lot of energy. For example when a star is sucked by a black hole the black hole emits the energy equivalent of the star.
Q: WHERE DOES SPACE BEGIN?
A: With reference to the Earth, space begins at the end of the atmosphere. But with reference to the Universe, space does not have a beginning.
Q: WHEN DID THE UNIVERSE BEGIN?
A: The widely accepted theory is that the Universe began in the Big Bang about 13.7 billion years ago. The theory of relativity predicted this and its predictions said that there must be a singularity. At singularities all laws of science are useless. So we must predict the past using quantum mechanics. This theory predicts that the universe does not have a beginning. So the Universe does not have a beginning.
Q: WHAT IS THE UNIVERSE MADE OF?
A: It is made of 70% dark energy, 20% dark matter, 6% ghostly neutrinos and 4% visible matter.
Q: HOW WAS OUR SUN FORMED?
A: In a cloud of gas on the other end of the galaxy, some mass began to collapse under its own gravity creating a protostar. Hydrogen atoms began to form from the helium atoms and this mass was transformed to energy. Thus the sun was formed.
Q: WHAT IS THE FUTURE OF THE SUN?
A: In about 5 billion years the sun will swell up to form a Red Giant as mentioned earlier and will throw of its outer layers. This is called a planetary nebula.
The star will shrink and become a white dwarf but not a singularity. The forces inside it would hold that from happening.
Q: WHAT IS THE FUTURE OF THE UNIVERSE?
A: There are many possible scenarios for the future of the universe. The future of the universe is governed by the two most recent findings of dark matter and dark energy.
Dark matter is something which can not be seen. It can only be studied by its force of attraction on other objects. Dark energy is also invisible. It can only be studied by its repelling force on other objects.
If there remains a steady level of dark energy and dark matter, there will be a big chill. The universe will slowly expand. Atoms will decay but time will still continue.
If there is too much dark matter, there will be a big crunch. The universe would collapse into a singularity.
If there is too much dark energy, there will be a big rip. Dark energy would be so strong that it would tear the forces between the atoms. Sadly, time would come to an end.
