The Hubble Space Telescope has created some amazing pictures of the cosmos during its 25 years in orbit, but that's not the only thing the telescope has accomplished.
Information gathered by the long-serving telescope has changed the way we understand the universe. Here are five important discoveries Hubble made possible in its quarter century orbiting Earth:
1. Pinning down the age of the universe
One of Hubble’s main tasks was to figure out the age and size of the universe. Researchers now know that the universe is about 13.7 billion-years-old thanks to research performed using Hubble's data.
In order to arrive at this figure, scientists used Hubble to measure the brightness of Cepheid variable stars — a special kind of star that pulses on a set cycle. The set pulsing makes these kinds of stars ideal targets to help scientists measure great distances in the universe because they already know the inherent brightness of the star. The Cepheid star will appear dimmer if it is farther away, giving researchers an easy way to gauge how distant its host galaxy is to Earth.
IMAGE: STSCI/NASA
“Knowing the age of the universe isn't just a matter of curiosity,” Hubble scientists said in a statement. “By giving us a time scale for the development of stars and galaxies, it helps us refine our models of how the universe — and everything in it — formed.”
2. Seeing galaxies in the early universe
In 1995, mission controllers directed Hubble to take a series of images looking at one small spot in the sky, and the results were astonishing.
The image created from that series of exposures revealed thousands of galaxies and quickly became one of Hubble’s most iconic views of the universe, called the telescope’s first deep field. The Hubble continued to take images of the deep universe through the course of its lifetime after multiple servicing missions by astronauts replaced cameras on the telescope.
“A series of deep fields taken with Hubble over the past 20 years — with each generation of Hubble’s cameras — has allowed astronomers to probe the star formation history of the universe over 95% of its lifetime,” Hubble astronomer Jennifer Lotz said during a press conference Monday.
IMAGE: NASA/ESA/HUBBLE
3. New moons of Pluto
Hubble was responsible for discovering four of the five moons that are currently known to orbit the dwarf planet Pluto.
The telescope’s observations of Pluto are actually helping NASA scientists plan the New Horizons mission, which is scheduled to fly by Pluto in July, by giving them more targets to observe during the historic flyby, Amy Simon of NASA’s Goddard Space Flight Center in Maryland said during a news conference Monday.
Hubble observations are also helping mission managers pick the best object for New Horizons to check out after it flies past Pluto this year.
“We now have two candidate targets,” says Simon, who has worked with Hubble for about 20 years. “The extended mission is under discussion now to see if it’ll be approved, but we know that there’s a place for it [New Horizons] to go, and that’s entirely due to Hubble.”
IMAGE: NASA/ESA/IRTF
4. Understanding seasons on other planets
Scientists using Hubble have also been able to track seasonal changes on planets. Hubble tracked Jupiter’s weather, for example, allowing researchers to see color changes in bands of clouds in the huge gas giant’s atmosphere.
Hubble also gave people on the ground an amazing view of a comet impacting another planetary body when Comet Shoemaker-Levy 9 crashed into Jupiter in 1994.
5. Exoplanet science
The Hubble telescope took the first image of a planet in visible light. The large planet, called Fomalhaut b, is about three times the size of Jupiter. Hubble has also been able to peer into the atmospheres of alien planets whenever they move across the face of their stars from Earth’s perspective. The telescope can also gather valuable data about a planet and its atmosphere as it travels behind its star.
“If you observe them while they orbit their stars, you can see the changing face of the planet presented to Hubble, and you can map the temperature of the planet not just on one side of the planet, but all the way around,” astronomer Jacob Bean said.
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