Wednesday, December 12, 2012

Spacing out has 19 graphics with explanations of the history, structure, and evolution of the universe. I will re-post here some of the things I learned from spending time at that blog post

How old was the universe when Earth was created? says 9.2 billion years old, and the universe is now 13.7 billion years old. Here is the overview they provide:

The stars are like the sun, obeying the same laws of physics.

Current estimates show that our universe is mostly composed of unknown forms of dark matter and dark energy, with familiar atoms being only a tiny fraction of the total.

The universe has many galaxies besides our own Milky Way galaxy. The universe is much larger than we formerly realized.

The farthest we can see:

The observable universe is everything that we can detect. It is a sphere 93 billion light-years in diameter, centered on Earth. We cannot perceive the entire universe at once, due to the slowness of the speed of light compared with the vast scale of the universe.

As we look out into space, we see objects as they were at earlier and earlier times in history. Also, because of the accelerating expansion of the universe, distant objects are much farther away than their age would have us think. For example, the edge of the observable universe is estimated to be about 46 billion light-years away, even though the universe itself is only 13.7 billion years old.

The true extent of the universe is unknown. It could be much bigger than the observable universe – perhaps even infinite in size. However, light from the most-distant regions would never be able to reach us; the space it must pass through is simply expanding too fast.

Physicists are trying to re-create on Earth the plasma that is thought to have comprised the early universe; they are using particle accelerators to smash subatomic particles together at high energy.

Nine billion years after the Big Bang, our solar system was formed.

Read and view much more here:

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