It’s been almost 22 years since NASA launched the Hubble Space Telescope, one of the most prolific science instruments ever built. Using a variety of instruments, Hubble has peered deep into space, bringing back never-before-seen images of stars, galaxies, explosions, and answers to cosmic questions.
Despite the revelations, in these trying economic times President Obama is looking to cut NASA’s funding, limiting the budget to just $17.7 billion in 2013, a five per cent cut from the budget proposed last year.
The planetary science division of NASA will pay the deepest price, with a 20 per cent reduction in its budget altogether. This division has been putting together the James Webb Space Telescope, the successor to the Hubble.
With the James Webb tentatively set to launch in 2018, we wanted to take a look at all the important things that the Hubble has discovered.
The prevailing theory on the creation of the universe says that the 'Big Bang' occurred and space has been expanding ever since. Before Hubble, most astronomers believed that the universe would continue to expand, but like a car without gas it would coast, slower and slower, losing speed as it went.
By measuring supernovae, Hubble determined the distance between galaxies that continued to grow farther apart. And scientists found that instead of slowing down, the universe's expansion is actually speeding up. The edges of the universe continue to propel faster and faster from the 'centre.'
This is also how scientists were able to determine, roughly, the age of the universe.
Before Hubble was sent into orbit, scientists could only guess at the inexact age of the universe -- something between 10-20 billion years.
But by measuring the luminosity of 31 Cepheid variable stars, Hubble was able to calculate the rate of the expansion of the universe, giving us a much more precise age estimate of 13.7 billion years old, give or take a few hundred million.
Before Hubble we were unable to study the most distant galaxies, which gave off light billions of years old. But by taking a risk and focusing the Hubble camera into the expanse of space for 10 days (most Hubble observations take just a few hours), the Hubble Deep Field was born.
The HDF is an image containing over 3,000 galaxies of various shape, size and luminosity. Studying this image gave astronomers a glimpse into the history of the universe, and allows us to see how galaxies are formed, grow, and eventually die.
Other projects, like the Hubble Ultra-Deep Field, have given us the deepest astronomical images that the naked eye can see.
When quasars were first discovered, their nature was largely unknown. They have incredible luminosity that first made astronomers believe they were looking at a star -- but these objects were too far from Earth to be in our own galaxy.
Using the Hubble, we were able to determine that quasars reside in the centre of a galaxy, and are powered by the friction created by a supermassive black hole. The amount of light and energy built up and released makes the quasar the brightest known object in the universe.
While studying quasars, Hubble astronomers realised that all galaxies with these bright centres had supermassive black holes in the middle. And the mass of the black hole (measured by how fast matter falls into it, since nothing can escape a black hole) is related to the mass of the stars clustered in the galaxy's centre.
This apparently indicates that the formation of a galaxy is connected to the formation of its black hole centre -- they are not separate creations.
Some of Hubble's most fantastic photographs are of the collapsing clouds of dust and gas that eventually form new stars. Previously, pictures of the clouds could only reveal the jets of dust that exploded out of a new star, not the spinning 'protoplanetary' disks that become a centre of a new planetary body.
But thanks to Hubble, astronomers can see these spinning disks, and through them have discovered new understandings of how stars are formed. New stars and solar systems are greatly influenced by their environment, which was indiscernible prior to photos in 1995 of the Orion Nebula.
Hubble can find extrasolar planets by watching the slight dimming of light that occurs when a planet comes between the telescope and its parent star.
These periods, called 'transits,' allowed Hubble to make the first measurements of the composition of the atmosphere of these planets -- some of which contain sodium, carbon, oxygen and other elements that we are familiar with on Earth.
Hubble's discovery of methane, the first known organic molecule on an extrasolar planet, is the first step to finding life in space.
Cosmic crashes give us a better understanding of our own cosmic neighbourhood — plus, they're really cool
Hubble caught a blow-by-blow account of a comet impact on the surface of Jupiter in 1994, which astronomers believed would be a once-in-a-many-lifetimes event. But another comet struck Jupiter in 2009, meaning that these occurrences may be less rare than previously thought (one in every thousand or so years was the original hypothesis).
By being able to observe the impact of the comet (in both visible and ultraviolet light), astronomers saw that the composition Jupiter is less like the Sun that previously thought. Being able to view the impact sites on such short notice will help us refine our understanding of the planets nearest to us, and beyond.
Gamma-ray bursts were first discovered by U.S. satellites looking to track nuclear blasts. What they found instead was daily, randomly placed explosions with power equal to 10 million billion Suns.
Unknown was why some supernovae explosions produced gamma-ray events when others did not. Thanks to Hubble, it seems that dying stars with low metal content produce black holes and gamma-ray bursts. Thus, spotting a gamma-ray perhaps means that you are witnessing the birth of a new black hole.
In the image to the right, a galaxy 12 billion light-years from Earth produced a gamma-ray burst that for one second was as bright as the rest of the universe combined.
Hubble has observed a number of dying stars, which look different depending on their size. Mid-size stars eject their gases and become white dwarfs, while massive stars collapse and a supernova occurs.
These events take place over many years, not in an instant. For white dwarfs, the glowing gas they emit form beautiful nebulae, while astronomers have been watching one particular supernova occur since 1987.
Watching supernovae and planetary nebulae over the years show that these transformations occur during a series of outbursts. Monitoring the lifecycle of these stars can help us understand how these events have and will continue to play out for the rest of time, across the universe.
NOW WATCH: Briefing videos
Business Insider Emails & Alerts
Site highlights each day to your inbox.