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What’s the atmosphere? Weather science

By | 2017-08-19T09:55:46+00:00 August 19th, 2017|Physics|

Did the Earth look like this right after it cooled down? The atmosphere is the air that is wrapped all around a planet. Not all planets have atmospheres. In order to have an atmosphere, the planet has to have enough gravity to hold on to light atoms like hydrogen and helium. It has to keep those atoms from floating away into [...]

What are stars made of? Astronomy, physics

By | 2017-10-14T16:41:05+00:00 August 19th, 2017|Physics|

The sun from space The earliest stars probably formed only a few hundred thousand years after the Big Bang that started the universe - maybe about 13.5 billion years ago. Stars are the oldest big objects in the Universe. Stars formed big clumps of hydrogen and a few helium atoms, the simplest kinds of atoms, and [...]

Neptune – Planets – Astronomy – Physics

By | 2017-08-19T01:25:54+00:00 August 19th, 2017|Physics|

Neptune from space Neptune is the farthest planet from our Sun. Neptune is the only planet that is so far away that you can't see it without a telescope. Neptune (NEPP-toon) is an icy planet, about the same size as Uranus. Neptune's probably a lot like Uranus in other ways, too. Neptune has a rocky core [...]

What is a nebula? Space and astronomy

By | 2017-08-19T01:15:01+00:00 August 19th, 2017|Physics|

The Eagle Nebula A nebula is a bunch of atoms and molecules floating in outer space, like a cloud of dust. More than one nebula are called nebulae, because -ae is the plural ending in Latin, just as -s is the plural ending in English. Nebula is the Latin word for a cloud. The earliest nebulae formed just [...]

Main sequence stars – Astronomy

By | 2017-08-18T17:56:46+00:00 August 18th, 2017|Physics|

A starry sky with the Milky Way galaxy(thanks to Bernd Nies) Nine out of ten stars that you see in the sky are main-sequence stars, and our sun is one of them. Most main-sequence stars probably started out as brown dwarfs, and then succeeded in getting enough mass together to begin a nuclear fusion reaction inside them. It's the energy from this [...]

Jupiter – Planets – Astronomy

By | 2017-08-18T17:46:33+00:00 August 18th, 2017|Physics|

Jupiter from space Jupiter (named after the Roman god Jupiter) is the next planet further out from our Sun after Mars. But Jupiter is much, much further away from the Sun than Mars is. If the Sun were the size of a penny, then Earth would be about six feet away from the Sun. And Mars would be about ten [...]

Nuclear physics – fission and fusion

By | 2017-08-17T17:00:35+00:00 August 17th, 2017|Physics|

Atomic bomb explosions make a "mushroom cloud" - this is a fission reaction Nuclear physics is the process of getting energy from the nucleus of an atom. There are two ways to release energy from atoms: fission and fusion. Fusion happens all the time in nature, mostly inside stars because fusion needs lots of heat or gravity to get it going. Fusion works with the [...]

Nuclear fusion – Simple Physics

By | 2017-08-17T16:55:26+00:00 August 17th, 2017|Physics|

The Sun shining from space Fusion reactions are how the first stars got started. Soon after the Big Bang, hydrogen atoms began bumping into each other and merging into one bigger heliumatom. Four atoms with four nuclei - centers - mixed together into one atom with a bigger nucleus. But each time this happened there was a bit of energy left [...]

What is helium? Atoms, elements, and chemistry

By | 2017-06-02T08:16:27+00:00 June 2nd, 2017|Chemistry|

Diagram of a helium atom Helium is a simple atom. The nucleus of a helium atom has two protons and two neutrons. Around the nucleus, there are two electrons. The only atom simpler than helium is hydrogen. There are helium atoms inside stars. The star makes helium by squashing four hydrogen atoms together into [...]