The science of expansion: Andromeda, gravity, and the ‘Big Rip’

If the universe is expanding in all directions, why is Andromeda hurtling toward the Milky Way?

  • The Andromeda Galaxy and our Milky Way are on a collision course that will obliterate life on Earth 4.5 billion years from now.
  • The universe is expanding in all directions, all at once – so why are Andromeda and the Milky Way drawing nearer? The gravity between them is a stronger force than expansion.
  • The rate of expansion is accelerating. If it continues to speed up, its force may become strong enough pull things apart that are currently held together by superior forces: Our galaxy, the solar system, and even the atoms in our bodies. That possible ending to the universe is known as the 'Big Rip'.

Black hole death: How extreme tidal forces turn humans into spaghetti

Getting to close to a black hole is a nightmare waiting to happen.

  • Like ocean tides caused by gravity, a nearby black hole would create a 'tide' inside your body, which is mostly water.
  • As your body drew nearer to the black hole, your head would be stretched away from your feet.
  • Scientists call this streching "spaghettification", from the word of spaghetti.
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Space toilets: How astronauts boldly go where few have gone before

A NASA astronomer explains how astronauts dispose of their, uh, dark matter.

  • When nature calls in micro-gravity, astronauts must answer. Space agencies have developed suction-based toilets – with a camera built in to ensure all the waste is contained before "flushing".
  • Yes, there have been floaters in space. The early days of space exploration were a learning curve!
  • Amazingly, you don't need gravity to digest food. Peristalsis, the process by which your throat and intestines squeeze themselves, actually moves food and water through your digestive system without gravity at all.
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Would scientists tell us about a looming apocalypse?

If a doomsday asteroid is set to collide with Earth, you're going to know about it – whether you want to or not.

  • NASA astronomer Michelle Thaller fields one question with a heavy heart: If scientists knew there was a catastrophic asteroid heading towards Earth, would they tell us?
  • What about aliens? Is NASA hiding aliens from the public? Are they "in" on conspiracy theories? Scientists are, on the contrary, eager to communicate their findings to the media and the public, says Thaller.
  • "To me it speaks to the separation that somehow scientists are this monolithic inhuman group; that we could hide things, that we would want to," says Thaller. No single telescope owns the sky. If there's a doomsday asteroid coming, scientists all over the world are going to let the world know about it.
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Great scientific discoveries hide in boring places

NASA's Michelle Thaller explains how an accidental discovery led to the 1978 Nobel Prize in Physics.

  • In 1964, two American radio astronomers, Arno Penzias and Robert Wilson, discovered the Cosmic Microwave Background by accident. Their resulting work earned them the Nobel Prize in Physics in 1978.
  • They had long been trying to get rid of the annoying "noise" in their data (even thinking it was all the pigeon poop in their telescope) only to realize the noise was the treasure. They had stumbled upon the oldest light in the universe, and some of the strongest evidence to support the Big Bang theory. (What is the Cosmic Microwave Background?)
  • That's why space and science are never boring, explains NASA astronomer Michelle Thaller. One scientist's junk data can be another's Nobel Prize.