Hubble Deep Field

One of the greatest images that have come from the Hubble Space telescope is the Hubble Deep Field (HDF) image. Astronomers selected one tiny region of the sky and imaged it for 10 consecutive days straight with the Wide Field and Planetary Camera 2 on Hubble. The purpose of the HDF was to find very distant very faint objects. The HDF image above is from the northern hemisphere and contains over 3000 sources, almost all of which are distant galaxies. The most distant galaxy in the image is ~12 billion light years away! This means we are seeing the galaxy as it appeared a mere 2.5 billion years after the Big Bang! (In astronomer terms that's very close to the beginning of the universe!)

You can also see the variety of different types of galaxies in this image. Some appear spiral shaped, which others appear more like fuzzy blobs, or point sources. HDF helped astronomers understand the properties of distant galaxies and how they are dispersed throughout the universe. A second HDF was taken in the southern hemisphere, and revealed a similar stunning image of the distant universe.

Image Credit: NASA/HST

Hubble's "Broken" Mirror

The Hubble Space Telescope is responsible for a majority of the pretty pictures you find online of stars, galaxies, supernova and other cool things. Hubble was launched on April 24th, 1990 on the space shuttle Discovery. It was placed in a low earth orbit, meaning that it orbits earth like a satellite, and is accessible by human beings. Hubble was supposed to be the best telescope ever launched at the time, but after Hubble transmitted back it's first images, scientists were very worried. Hubble should have sent back crystal clear images, but instead we received fuzzy out of focus images. The problem was that the 2.5m mirror was improperly shaped. It should be a perfectly smooth and specifically curved piece of glass, but during the polishing process, the glass was flattened by an extra 2.2microns (~1/1000 of a millimeter). This tiny error resulted in a huge error in imaging as can be seen below. 

 

                                               Galaxy before corrections                      Galaxy after Correction

The image on the left was taken with the original mirror, while the image on the right was taken after an adaptive optics system was placed on the telescope to correct for the error. Good thing we placed Hubble in an orbit where we could get to it!

Stay tuned for more information about Hubble, as we lead up to it's 21st Birthday on Sunday!

Fun fact for those who live in Rochester, NY: Hubble's mirror was constructed by Perkin-Elmer company. Kodak was contracted to build the exact same mirror as a backup, in case something went wrong. The stubborn people at Perkin-Elmer refused to let Kodak check their work, and therefore the mirror error was not caught until after Hubble was launched. The mirror Kodak built is now on display at the Smithsonian Institution, and is 100% correct. Yay Kodak!

Image Credit: NASA/HST

End of the Shuttle Program

 NASA Space Shuttle Endeavour

Many of you may have heard talk of the end of NASA's shuttle program. Sadly, it is true. NASA no longer has funding for manned space flight missions. (One of the many budget cuts that we are all dealing with nowadays.) This doesn't mean that NASA isn't launching things to space, it just means that they are no longer sending humans to space. There are two missions left, one using Space Shuttle Endeavour, the other Space Shuttle Atlantis. Both missions are scheduled to launch from Kennedy Space Center in Florida early this summer. NASA will still launch satellites, telescopes, rovers, and other goodies into space, but until the government grants us more money, space will have to be studied using robotic instruments. Other agencies, such as the European Space Agency, will continue manned missions to the international space station as funding permits. So if you want to be an astronaut, you'll have to move out of the United States. *sadness*