April 24 marked the 30th anniversary of the Hubble Space Telescope (HST), which has given humanity some of the most awe-inspiring images of the cosmos ever taken. Hubble has revealed sights never seen before, and new views of old favourites, including planets, stars, nebulas, galaxies and black holes.
Hubble was launched on April 24, 1990 from the Kennedy Space Center, aboard the space shuttle Discovery. It’s cameras turned on and took in the views the next day from low Earth-orbit. Read our 2-part look back at that incredible shuttle mission flown 30 years ago HERE!
“Hubble has given us stunning insights about the universe, from nearby planets to the farthest galaxies we have seen so far,” said Thomas Zurbuchen, associate administrator for science at NASA Headquarters in Washington, D.C. “It was revolutionary to launch such a large telescope 30 years ago, and this astronomy powerhouse is still delivering revolutionary science today. Its spectacular images have captured the imagination for decades, and will continue to inspire humanity for years to come.”
Hubble helped to revolutionize modern astronomy. Some of its greatest accomplishments include measuring the expansion and acceleration rate of the universe; finding that black holes are common in galaxies; characterizing the atmospheres of some exoplanets orbiting distant stars; monitoring weather on planets in our own solar system and chronicling the birth and evolution of stars and galaxies by looking back in time across 97% of the observable universe.
Hubble alone has produced 1.4 million observations and the data it has sent back to Earth has been used in more than 17,000 peer-reviewed science publications to date, surpassing any other space observatory.
One big advantage of Hubble is that it can be serviced and upgraded as needed in orbit by astronauts. Crews on the space shuttle did this five times between 1993 and 2009.
“The Hubble Space Telescope has shaped the imagination of truly a whole generation, inspiring not only scientists, but almost everybody,” said Günther Hasinger, Director of Science for the European Space Agency. “It is paramount for the excellent and long-lasting cooperation between NASA and ESA.”
But now, what about the next 30 years? What else will Hubble discover, as well as other space telescopes that are either awaiting launch or on the drawing boards?
Probably the most-anticipated upcoming mission is the James Webb Space Telescope (JWST). After facing many delays, it is now scheduled to launch in 2021. It will be an infrared observatory that will complement and extend the discoveries of HST, with longer wavelength coverage and greatly improved sensitivity. JWST will be able to look further back, closer to the beginning of time and hunt for so-far unobserved formation of the first galaxies. It will also study exoplanets and look inside dust clouds where stars and planetary systems are forming today.
“What we’re trying to do is look at the birthplaces of massive stars,” explained Erick Young, principal investigator of a program that will use Webb to study this phenomenon. “Determining the actual structure of the clouds is very important in trying to understand the star formation process.”
“These forces destroy the birth environment that the star was created in,” explained infrared-dark-cloud expert Cara Battersby, an assistant professor of physics at the University of Connecticut. “The environment you’re looking at after it formed is totally different from the environment that was conducive to its forming in the first place. And since we know that infrared-dark clouds are places where massive stars can form, if we look at their structure before stars have formed or have just started to form, we can study what environment is needed to form those massive stars.”
Primary mission goals include:
- Search for the first galaxies or luminous objects formed after the Big Bang
- Determine how galaxies evolved from their formation until now
- Observe the formation of stars from the first stages to the formation of planetary systems
- Measure the physical and chemical properties of planetary systems, including our own Solar System, and investigate the potential for life in those systems
One of the most exciting aspects of JWST is that it will be able to study the atmospheres of potentially habitable exoplanets, and look for possible biosignatures – chemical evidence of life. This includes the TRAPPIST-1 system and others.
“The atmospheres are harder to detect but the reward is higher. It would be very exciting to make the first detection of an atmosphere on an Earth-sized planet,” said David Lafrenière of the University of Montreal, principal investigator on one of the teams examining TRAPPIST-1.
The TRAPPIST-1 system has seven known planets, all nearly the same size as Earth, and at least three of them are considered to be potentially habitable.
“It’s a coordinated effort because no one team could do everything we wanted to do with the TRAPPIST-1 system. The level of cooperation has been really spectacular,” explained Nikole Lewis of Cornell University, the principal investigator on one of the teams.
“With seven planets to choose from, we can each have a piece of the cake,” added Lafrenière.
JWST will also take a closer look at the ice giants Uranus and Neptune in the outer solar system. They have not been visited again yet since the Voyager 2 mission in the 1980s, so in the meantime, Hubble has been providing the best views since then.
“The key thing that Webb can do that is very, very difficult to accomplish from any other facility is map their atmospheric temperature and chemical structure,” said Leigh Fletcher, an associate professor of planetary science at the University of Leicester in the United Kingdom. “We think that the weather and climate of the ice giants are going to have a fundamentally different character compared to the gas giants. That’s partly because they’re so far away from the Sun, they’re smaller in size and rotate slower on their axes, but also because the blend of gases and the amount of atmospheric mixing is very different compared with Jupiter and Saturn.”
Another exciting upcoming mission is the Wide Field Infrared Survey Telescope (WFIRST). It is slated to launch in the mid-2020s, and will have a panoramic view of the universe 100 times wider than Hubble.
Like JWST, it will be a wide-ranging mission. The Wide Field Instrument will measure light from a billion galaxies over the course of the mission lifetime. It will search for exoplanets, performing a microlensing survey of the inner Milky Way to find an estimated ~2,600 new worlds (or more!). To assist this, the Coronagraph Instrument will block the light of the host stars to perform high contrast imaging and spectroscopy of individual nearby exoplanets. WFIRST will complete the statistical census of planetary systems in our galaxy.
WFIRST will examine cosmic mysteries such as why the expansion of the universe seems to be accelerating and look for additional evidence of dark energy. It will also study supernovae and galaxy clusters, map out the distribution of galaxies in three dimensions, measure the precise distances to galaxy clusters to map how they grew over time, and measure the matter in hundreds of millions of distant galaxies through a phenomenon called gravitational lensing.
WFIRST will be sensitive enough to find planets smaller than Mars, and reveal planets orbiting their host stars at distances ranging from closer than Venus to beyond Pluto. This will make it a great companion to the Transiting Exoplanet Survey Satellite (TESS), which is already in space, fully operational and finding many new exoplanets.
TESS was launched on April 18, 2018, and has taken over from the now-completed Kepler mission, which discovered thousands of new exoplanets. TESS will survey over 85% of the sky, 400 times larger than covered by Kepler, and is searching for planets around nearby stars (less than about 200 light-years away).
TESS recently discovered its first Earth-sized exoplanet – called TOI 700 d – in the habitable zone of its star, where temperatures could allow liquid water to exist. It is 101.5 light-years from Earth.
“TESS was designed and launched specifically to find Earth-sized planets orbiting nearby stars,” said Paul Hertz, astrophysics division director at NASA Headquarters in Washington. “Planets around nearby stars are easiest to follow up with larger telescopes in space and on Earth. Discovering TOI 700 d is a key science finding for TESS.”
Hubble has revolutionized our understanding of the universe in the past 30 years, and should continue to do so for years to come. And now, joined by new space telescopes like TESS, JWST and WFIRST, the next 30 years should be an even more incredible time of discovery.
You can find more information about Hubble and see thousands of cool photos on the mission website.