Deep Space Inhabitants - Galaxies

Credit: NASA/Hubble Heritage Team (STScI/AURA)

Heaven's net casts wide.
Though its meshes are coarse, nothing slips through. - Lao Tzu

While the various spacecraft have been flying through the solar system to bring us images of the planets, the Hubble Space Telescope has been quietly orbiting the Earth for 18 years, capturing extraordinary pictures of deep space, including gorgeous images of galaxies.

It's hard to believe, but it wasn't until the early 20th century that astronomers began to seriously think that what they had been calling "spiral nebulae" might actually be star systems beyond our own Milky Way galaxy. With advances in the optics of telescopes, it became clear that these nebulae were not new solar systems forming within the Milky Way, as was previously thought. As it stands now, astronomers calculate there are 100 billion galaxies in the universe; each contains between 10 million and a trillion stars.



Those are the kinds of numbers that make it hard for people to get their minds around astronomy, especially when it comes to extragalactic phenomena. This video tries to make the numbers easier to understand, and also explains two deep field images taken by Hubble. They revealed a surprising number of galaxies in two areas of the sky that were thought to be pretty empty. Whether they're among the most important images ever taken, as the video claims, I'll leave to your judgement. They certainly are amazing.

For more galaxy images, maybe to update your screen saver, check the Hubble gallery site. You can also find images of galaxy collisions that were recently released.

There's always a danger when discussing the vastness of the universe that a person might end up feeling insignificant, like a single grain of sand on a beach. But here's another perspective to consider, from writer Timothy Ferris:

The reassuring aspect of the portrait of the universe we now see drawn across the sky lies in its reconciliation of humanity with the material world. That we are part of the galaxy is literally true. The atoms of which we are formed were gathered together in the toilings of a galaxy; their fantastical assembly into living creatures was nourished by the warmth of a star in a galaxy; we look at the galaxies with a galaxy's eyes. To understand this is to give voice to the silent stars.