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Asked by farhanak to Adam, Catherine, Karen, Leila, Nazim on 13 Mar 2012. This question was also asked by chrisvw, tonieastup123.
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Adam Stevens answered on 10 Mar 2012:
All of space and time was created in the Big Bang. (What caused the Big Bang, we don’t know.)
Our Earth was created from a great big cloud of stuff leftover from the explosion of an old star. This cloud gradually came together due to gravity, created our Sun, and condensed into solid matter.
Gradually these bits of stuff started clumping together to make the planets.
The rocky stuff, which doesn’t melt that easily were the bits that stayed near the Sun, which is where it’s hotter. That’s why the central planets are rocky.
The stuff that melted easier didn’t clump together where it was warm, but further out where the Sun couldn’t warm things up, they could. That’s why the outer planets are mostly ice and gas.
So the Earth formed from bits of rocky stuff that bashed together (like asteroids).
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Leila Battison answered on 10 Mar 2012:
We have no evidence to suggest that space, or the universe was created by *anyoneMATOMO_URL Science can collect information that points towards physics and chemistry combining over huge amounts of time to create everything we see in the universe and much more.
The universe started about 13.7 billion years ago with the Big Bang – at this time all the energy and matter were in place to make stars and planets and galaxies.
The sun and our planet are really young compared with this – only 4.5 billion years old! The sun started burning hydrogen and helium gas left over from an old exploded star, and heavier elements like silicon and oxygen, came together to make rock and water and other things that planets are made of. In a spinning disk around the new sun, the rock and ice all pulled together because of gravity, and melted into big balls that we now call planets.
Over time since the earth was formed, it cooled down, comets crashed into it and delivered the water that makes up our oceans, and carbon and other elements got together to make life. Four billion years of volcanoes, earthquakes and evolution and here we are today! All explained by what we can study in the rocks and the skies.
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Nazim Bharmal answered on 10 Mar 2012:
We don’t know how the big bang started and I can’t even imagine what it was like. There was no “before” because there was no time—this is really difficult to understand for me.
Then, like Adam said, basically gravity caused what was created (mainly simple gases) to coalesce, which basically means stick together. First galaxies without stars, then the first stars, then they died and new stars were made, and eventually dust was created with ice and other stuff.
One day the sun was created, although it actually took millions of years for the core of the Sun to start producing heat and light, and eventually the Earth came together from the dust and ice. We think that the moon was created when another planet which doesn’t exist anymore hit the Earth and smashed it up a bit, leaving some rocks in orbit which coalesced (that word again) to make the moon. We also think that the oceans and seas came from ice that was trapped in the earth and slowly came up to the surface and melted.
After the earth was made, it took a long time but one day life started. We have no idea how, but perhaps because of lightning hitting some chemicals which (luckily) for us “started” the first reactions that created tiny creatures.
The rest of the story is geology and geography, so I’ll let you discover that yourself.
The most important ingredient which is needed is gravity; no gravity, no planets, stars, galaxies, and no scientists.
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Karen Masters answered on 13 Mar 2012:
Well the Earth was made our of a giant disc of debris orbiting the baby Sun. Once a tiny Earth started forming it attracted more and more material because of it’s gravity.
But then you ask where the baby Sun and debris disc came from – well it formed when a giant interstellar cloud of gas started collapsing. The centre got hot enough to start fusing hyrogen atoms – and the Sun was born. The leftovers ended up in a rotating disc and formed the planets.
But then where did the gas cloud come from – well it’s part of our galaxy…
So the galaxy – well it formed by gravity pulling material together after the Big Bang – we see an imprint of the tiny fluctuations in matter formed by quantum physics in the vast structures of the “cosmic web” of galaxies.
So then the Big Bang and all the matter – well that’s where current Physics stops working, so your guess is as good as mine for that….
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