Even if you know nothing about astronomy you have probably heard about Hubble. The Hubble Telescope was launched in 1990 with the hopes that it would answer the question of how our universe works, and just how old it really is. It did not take long for Hubble to answer those questions, and provoke even more! Although astronomers learn a little bit more with every observation that Hubble makes, 10 of these discoveries stand out from the crowd.
May 25, 1994; "Hubble Confirms Existence of Massive Black Hole at Heart of Active Galaxy"
Before Hubble's study on M87 (an elliptical galaxy only 50 million light years away), black holes were little more than a theory, or a "mathematical curiosity". Using the Faint Object Spectrograph to measure the speed of the gas orbiting around the center of M87, astronomers found that the gas on one side was barreling away from planet earth at over 1.2 million miles per hour! Yet it does not disperse, but stays in orbit around a relatively small but dense space. In the future, Hubble discovered that black holes not only exist, but are a common occurrence throughout the universe!
June 13, 1994; "Hubble Confirms Abundance of Protoplanetary Disks around Newborn Stars"
Planets have to form somewhere right? Hubble revealed that an estimated half of new stars are surrounded by flat clouds of dust. These disks, now called "proplyds" are a breeding ground for planets and the beginnings of new solar systems. The abundance of these proplyds reinforces the belief that solar systems and planets are common in the universe, and that there is a possibility for life elsewhere in the universe. On November 20, 1995, a larger photo of a region in the Orion Nebula sheds greater light on the process of forming solar systems.
October 26, 1994; "Hubble Space Telescope Measures Precise Distance to the Most Remote Galaxy Yet"
(News Release #: STScI-1994-49) M100 was the farthest Galaxy whose distance could accurately be measured. In 1929, Edwin Hubble originated the "Hubble constant". Defined as the ratio of the speed of recession of a galaxy (due to the expansion of the universe) to its distance from the observer (Princeton); the Hubble constant is used in relation to Cepheid stars. But his numbers had a ratio of over 15% uncertainty. The Hubble Telescope is continuously refining this number; as a result we now have a more accurate estimate of how old our universe is. It was once believed to be between 10-20 Billion years old. Now the window has narrowed down to 13-14 billion years old. November 19, 1996; "Hubble Surveys the "Homes" of Quasars" (News Release #: STScI-1996-35) Elusive Quasars have perplexed astronomers for years. Quasars are about the size of our solar system, but they are hundreds of billions of times brighter than any star! Although they were discovered in 1963, it wasn't until Hubble that scientists were able to see just where they were located. This new information links them to galactic collisions and black holes.
March 11, 1999; "Hubble Views Home Galaxy of Record-Breaking Explosion"
A star is born; or in this case, a star implodes, creating the biggest brightest explosion ever recorded at the time. Brighter than one million galaxies, if this burst of gamma rays was close to us our ozone would have been completely destroyed. No need to worry though, through further studies, NASA found that long-duration gamma ray bursts (1-2 seconds) are unlikely in our Galaxy. They are more likely in smaller, irregular galaxies that are low in the heavier elements.
November 27, 2001; "Hubble Makes First Direct Measurements of Atmosphere on World Around Another Star"
150 light years away Hubble found a planet about the size of Jupiter. But what is amazing about this discovery is that Hubble could detect elements on this planet; sodium, hydrogen, carbon and oxygen, all of which are necessary for life. Life on this planet is unlikely however, because it is so close to its sun, that it is heated to over 2000 degrees Fahrenheit. This proved that Hubble can analyze the composition of far away planets, and could even be used to find alien life.
February 19, 2004; "Supernova Shock Wave Is Producing a Spectacular New Light Show"
Another star is destroyed, but this one wasn't small and unstable, it is quite large and died of old age. Another image released September 09, 2004, shows a supernova shedding off layers of mass before it dies. Once thought to be uniform, the sharp eye of the telescope revealed that, like snowflakes in a winter storm, no two nebulae are alike. If you are worried about our sun exploding, don't be. The sun in our solar system is only a "medium" sized sun, and will gently puff off its outer layers until it becomes a white dwarf.
March 9, 2004; "Hubble's Deepest View Ever of the Universe Unveils Earliest Galaxies"
Hubble looks deeper into the Universe than ever before, using "Hubble Ultra Deep Field" to take a million-second long exposure. This snapshot reveals galaxies that existed within an estimated 800 million years of the big bang! It is in essence a look back in time, a look back to the very beginnings of the universe. One of the purposes of HUDF is to see if the universe is the same in its earliest times at it was around 1-2 billion years. Surprisingly, many of the galaxies in this image are very different from the elliptical and spiral galaxies we see now. Some of these were shaped like toothpicks, some appear chain-linked, and some even seem to be interacting with each other! With this new information it will be much easier to see how the universe has evolved and how galaxies are born.
February 20, 2004; "New Clues About the Nature of Dark Energy: Einstein May Have Been Right After All"
Dark energy is mysterious force that works in opposition to gravity. In the big bang theory the universe is expanding, but because of its sheer mass, and because of gravity, the rate of expansion should slowly decelerate over time. For 3 years two teams of astronomers; using land based telescopes; competed to find out just how much the expansion of the universe was decelerating. When it was finally time to crunch the numbers, they were negative. The universe isn't decelerating at all. In fact it is accelerating! These observations would mean that the founded understanding of how the universe worked was incorrect. A discovery of this magnitude would likely be taken with a large dose of skepticism. These findings could have turned up this way for a number of reasons. Because it depended directly on observing supernovae, the astronomical community turned to Hubble to take a more precise look into just what was going on. The findings were correct! This means a whole new range of possibilities for our universe. If the dark energy is stable, than it will last forever, continuously expanding and accelerating. But if the force is unstable, it could either come unglued (the Big Rip); so much so that even atoms will fall apart. Or it could reverse and cause the universe to implode on itself (the Big Crunch). Only the Hubble can really see far enough into space to get good clues about dark matter. When it finally comes time to leave orbit, there will have to be a successor, until then the project will have to be put on hold.
March 12, 2009; Hubble Provides New Evidence for Dark Matter Around Small Galaxies
Dark matter is not nearly as revolutionary as dark energy. Dark matter makes up a vast majority of our universe. It cannot be seen or explained. It is thought to be the "glue" that holds galaxies together.
If you would like to know more about the Hubble Space Telescope, visit http://hubblesite.org/. A complete archive of Hubble's news releases can also be found at :http://hubblesite.org/newscenter/archive/releases/.