"My God, it's full of galaxies!"

Scientists now believe we have underestimated the number of observable galaxies by a factor of 10. That's right, instead of 200 billion galaxies it is more like 2 trillion. That also means a heck of a lot more planets and places for life.

A team lead by Christopher Conselice of the University of Nottingham, U.K., looked at one small patch of sky and discovered 10 times more galaxies than ever expected.  His team used data taken from the Hubble Space Telescope and other observatories.  This sampling appears to be similar to the Kepler approach when it too viewed a patch of sky to project the sample of discovered exoplanets to entire night sky.  You can read the team's paper here.

Conselice noted:

It boggles the mind that over 90 percent of the galaxies in the universe have yet to be studied. Who knows what interesting properties we will find when we discover these galaxies with future generations of telescopes? In the near future, the James Webb Space Telescope will be able to study these ultra-faint galaxies,

The quote in the title of this piece comes from the HubbleSite, which notes:

In Arthur C. Clarke's novel "2001: A Space Odyssey," astronaut David Bowman exclaims, "My God, it's full of stars!" before he gets pulled into an alien-built wormhole in space. When the Hubble Space Telescope made its deepest views of the universe, astronomers might have well exclaimed: "My God, it's full of galaxies!"

As is often the case, reality mimics science fiction and then runs with it far beyond what we imagined.

Great Image: Colliding Spiral Galaxies

The image above is from NASA's Astronomy Picture of the Day website and represents the combination of galaxies, a process that will continue for billions of years.  Our own Milky Way galaxy has abosorbed other galaxies in the past and is expected to have more collisions in the future.  Here is the story for the image above:

Billions of years from now, only one of these two galaxies will remain. Until then, spiral galaxies NGC 2207 and IC 2163 will slowly pull each other apart, creating tides of matter, sheets of shocked gas, lanes of dark dust, bursts of star formation, and streams of cast-away stars. Astronomers predict that NGC 2207, the larger galaxy on the left, will eventually incorporate IC 2163, the smaller galaxy on the right. In the most recent encounter that about peaked 40 million years ago, the smaller galaxy is swinging around counter-clockwise, and is now slightly behind the larger galaxy. The space between stars is so vast that when galaxies collide, the stars in them usually do not collide.

Image Credit: Debra Meloy Elmegreen (Vassar College) et al., and the Hubble Heritage Team (AURA/STScI/NASA)