The Hubble Space Telescope was launched on April 24, 1990 – a quarter century ago! Since then (admittedly with a couple hiccups) it has been peering deeper into the cosmos than any telescope in human history. We have learned more about the origin of the universe, the makeup of galaxies, and distant worlds though Hubble’s eye – and with great effort from many researchers around the world.
Hubble is a joint project of NASA and the European Space Agency (ESA). Hubble weighs in at 11,000 kg, is 13.2 m by 4.2 m, and has a 2.4 m diameter primary mirror. Hubble coasts along in orbit at a cool 25,600 km/h at an altitude of 555 km above the surface of the Earth.
Hubble’s direct successor in space will be the James Webb Space Telescope, set for launch in 2018 – though Hubble is still expected to be in operation. Numerous next generation ground-based telescopes will also come online between 2020-2025, including the Thirty Meter Telescope (read in detail about TMT here).
To celebrate Hubble’s 25th birthday, the Hubble team released a new image from Hubble today: an image of the cluster Westerlund 2 and its surroundings.
This NASA/ESA Hubble Space Telescope image of the cluster Westerlund 2 and its surroundings has been released to celebrate Hubble’s 25th year in orbit and a quarter of a century of new discoveries, stunning images and outstanding science. The image’s central region, containing the star cluster, blends visible-light data taken by the Advanced Camera for Surveys and near-infrared exposures taken by the Wide Field Camera 3. The surrounding region is composed of visible-light observations taken by the Advanced Camera for Surveys. (Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), A. Nota (ESA/STScI), and the Westerlund 2 Science Team)
Even after 25 years, Hubble continues to impress with its images and scientific discovery to this day. For instance, Hubble data recently contributed to strengthening the hypothesis that Jupiter’s largest moon Ganymede has a massive subsurface ocean of liquid water.
One of the best videos I’ve been able to find that offers an overview of the Hubble mission is from the telescope’s 15th birthday, back on April 24, 2005. It’s worth a watch, and of course add another decade (!!) worth of discovery on top:
On top of several physical celebrations going on around the world for the occasion of #Hubble25, there is also a lot of great content on social media:
And remember a couple years ago when the Defense Department donated two better-than-Hubble space telescopes to NASA? Read here for that one.
It’s a big universe and we need all the eyes we can get to help unravel its mysteries.
The Canadarm on board The Space Shuttle Discovery releases Hubble in April 1990. (Credit: NASA/ESA)
And a fun (patriotic Canadian) fact: the last piece of hardware to come into physical contact with Hubble was the Canadarm on board the Space Shuttle Atlantis on mission STS-125 in May 2009, following the conclusion of Hubble Servicing Mission 4, the last mission to visit the telescope:
Canadarm lifts the Hubble Space Telescope out of the payload bay of Atlantis, moments before it is released into space following the successful repair mission of STS-125. (Credit: NASA)
The Thirty Meter Telescope (TMT) will help solve some of the deepest mysteries of the universe and will be the largest, most advanced telescope ever built when it opens.
TMT has also been in the news off and on for a number of years as the project has moved through its proposal and design phases, dating back to 2003.
But recently it has been in the news in a big way (particularly in Canada), as Prime Minister Stephen Harper and Industry Minister James Moore announced that the Canadian government would provide an additional $243.5 million (approx. $200 million USD) over 10 years in funding for the construction of the next-generation telescope.
This money will be spent primarily in three areas: construction of the metal frame for the telescope dome (to be built by Dynamic Structures Ltd.); Supplying the advanced adaptive optics system, a centrepiece of the TMT design (the National Research Council of Canada is managing this), and; operating costs.
Canada already contributed about $30 million during the design phase, and the Association of Canadian Universities for Research in Astronomy (ACURA) has played a significant role – alongside the University of California (UC) and the California Institute of Technology (Caltech).
What follows is a plain language overview of the TMT project and what the Canadian funding means for it.
A schematic of the Thirty Meter Telescope (Source: TMT).
The Thirty Meter Telescope will be, in short, the largest and most advanced ground-based optical observatory ever built when it is completed sometime in 2022.
The project is led by a consortium of UC and Caltech. Those two schools between them account for a 25% stake in the project. Japan is also on board with a 20% stake. Canada comes next, with the $243.5 million accounting for a 15-20% stake. China and India each have a 10% stake.
With Canada’s contribution in place, the TMT has achieved 80% of the capital funding required, and the team continues to negotiate with other potential partners to secure the remaining funds. Construction though is underway, with the ground-breaking that took place in October 2014 officially kicking it off.
There are whispers the U.S. will come on board via a National Science Foundation (NSF) grant, but as yet that hasn’t happened.
TMT will be built atop the Mauna Kea volcano in Hawaii, with an elevation of about 4 kilometers.
The observatories atop Mauna Kea, Hawaii include, from left to right foreground: the UH 0.6-meter telescope (small white dome), the UK Infrared Telescope, the UH 2.2-meter telescope, the Gemini Northern 8-meter telescope (silver, open) and the Canada-France-Hawaii Telescope. On the right in the background are the NASA Infrared Telescope Facility (silver), the twin domes of the Keck Observatory and the Subaru Telescope (Source: University of Hawaii).
In telescopes, size matters, and so the TMT’s primary mirror at 30m (98 feet) will be three times larger than the current largest, the Gran Telescopio Canaris (10.4m, opened in 2007) at La Palma in Spain’s Canary Islands. The extra diameter will provide TMT with ten times the light collection ability.
The same size comparison holds true for the twin W. M. Keck Observatories (10m each), which will coincidentally be TMT’s neighbours at Mauna Kea. And while second in size, Keck is often considered one of the most advanced optical telescopes currently in operation thanks to the highly advanced adaptive optics they were retrofitted with about a decade ago (more on adaptive optics later). Keck 1 opened in 1993 with Keck 2 following in 1996.
Another famous telescope – perhaps the most famous – is of course the Hubble Space Telescope, launched in 1990. TMT will have 144 times (!!) the light collection ability over Hubble’s 2.4m mirror. TMT will also provide about 10 times better image resolution.
The Horsehead Nebula (Source: NASA/Hubble Space Telescope). TMT will have 144 times more light collection and 10 times better resolution than Hubble.
Though by the time TMT is completed, there will be other kids on the telescopic block.
The Giant Magellan Telescope at Las Campanas Observatory in Chile will likely have opened – it’s currently looking to be completed in 2021. Though at 25.4m, the GMT’s rein as world’s largest telescope will be short-lived. Of course, 25.4m is nothing to sneeze at – it will still be 2.5 times larger than the present-day biggest.
Similarly, TMT will only be the world’s largest for a few short years. Sometime around 2024-2025 the European Extremely Large Telescope (don’t you love the naming convention for these bad boys?) is expected to be completed at the European Southern Observatory (ESO) in the Atacama Desert, Chile. The E-ELT’s primary mirror will be fully 39.3m in diameter.
These three mammoth ground telescopes – the GMT, TMT, and E-ELT – represent a generational leap forward in terms of size, technology, and ability to peer deeper into the cosmos than ever before.
As a scale comparison, imagine a professional baseball stadium. If the TMT were placed on the pitcher’s mound, the primary mirror would nearly fill the entire infield. The structure is also 22-stories tall.
But why does size matter so much?
It matters because the size of the mirror is directly proportional to the amount of light the telescope has the ability to collect. And more light means the telescope is able to produce sharper images and detect fainter objects, allowing the astronomers to see objects and detail that otherwise wouldn’t be possible.
In your own life, consider the difference between a point and shoot camera and a D-SLR. In some cases the D-SLR has a better sensor than the P&S, but not always. So why does the D-SLR capture better images (particularly in low-light), assuming an equivalent sensor? Because the optics in front of the sensor capture more light, allowing the shutter to fire faster, and in turn create a sharper image. (I realize this isn’t a complete analogy, but I hope it sheds some [pardon the pun] light on why size matters.)
But, if it’s so important to have telescopes collect the maximum amount of light, why haven’t they been built this large before? A couple reasons.
First, as it often boils down to, is money. Building large telescopes is expensive (both TMT and E-ELT come with a total price tag between $1 and $1.5 billion each). But money alone only really tells part of the story here.
The underlying basis for why telescopes haven’t been built this large before is the second reason: technology. The relevant advances in technology are similarly revealed mainly in two places: segmented mirrors and adaptive optics.
Segmentation allows huge mirrors to be broken down into smaller pieces, which in turn allows for more straight forward construction, transportation, maintenance, and so on – all of which reduces cost. Large mirrors are extremely difficult to manufacture, heavy to support, and challenging to move around. For instance, could you imagine a 30m single piece of glass being moved up the side of a 4km tall volcano in Hawaii, to say nothing of getting it to the island in the first place?
TMT has two additional mirrors: a secondary (3.1m) and a tertiary (elliptical, 3.5×2.5m). The secondary mirror is placed above the primary mirror in order to collect the light from it. The secondary mirror then reflects the light back down towards the tertiary mirror, which directs the light to the instrument suites.
The 30m TMT primary mirror will actually be made up of 492 smaller mirrors. Each hexagonal piece of glass being 1.4m long corner to corner, spaced 2.5mm apart, and 4.5cm thick.
It’s worth mentioning though that TMT won’t be the first telescope with segmented mirrors; it was pioneered on Keck, and since used on other observatories as well, including the Gran Telescopio Canaris. GMT, E-ELT, and the next generation James Webb Space Telescope (set to launch in 2018) will all employ segmented mirrors, too.
But mirrors, no matter how large, won’t do you much good if you can’t get a clear view of the sky – and that’s where adaptive optics comes in.
Any telescope on Earth has to contend with the atmosphere. That blanket of layers of fluid air, all swirling around and wreaking havoc on anyone trying to get a clear view of objects in space – particularly small or faint objects, which coincidentally are the focus of a great deal of astronomy nowadays.
Even with your own eyes you have to contend with atmospheric turbulence if you happen to go out stargazing. That twinkling you see when you look at stars? That is actually caused by turbulence in the atmosphere distorting the light as it passes through (the stars don’t really twinkle at all, at least not for the purpose of this discussion).
Telescopes have to contend with the same interference, and the result – if left uncorrected – are blurry images that lack the required level of detail that astronomers require to push the frontier of understanding further forward.
In order to overcome this, a way has been devised to correct for the atmosphere by manipulating the shape of the mirrors in the telescope. Two corrective mirrors in TMT will have highly precise actuators attached, which will be able to very finely reshape each mirror in real-time to create a clear image.
Left: The Galactic Center without adaptive optics (Source: Keck Observatory). Right: The Galactic Center and central black hole, Sgr A*, with adaptive optics (Source: Keck Observatory and the UCLA Galactic Center Group).
The physics behind this technology, in a nutshell, is that when light is disturbed by the atmosphere it creates a distortion in the light wave. By reshaping the mirrors, an opposite distortion can be created in the telescope, cancelling out the atmospheric distortion.
The TMT’s actuators are controlled by a computer system, which in turn relies on a system that measures atmospheric turbulence. This measurement is accomplished by either pointing the telescope towards a guide star or firing a laser beam into the sky to create an artificial star, which the telescope can then image in order to measure the distortion and correct for it in real time.
Similar to segmented mirrors, TMT isn’t the first telescope to make use of a new technology. Others, including Keck, have been retrofitted with these optical systems as the technology has developed over the last decade. TMT is however the first telescope ever to be constructed with adaptive optics as a core piece of the design.
TMT, many like other telescopes, is also being constructed in a place where the impact of weather (including cloud cover) will be minimized. In being on top of a mountain 4km above sea level, TMT will not have to deal with as much weather as it would at a lower elevation. Being higher up also helps to reduce some of the atmospheric distortions, as the thickest part of the atmosphere is the part closest to sea level.
An illustration of the Thirty Meter Telescope’s laser guide system (Source: TMT).
More light, higher resolution, clearer view – what do they hope to find?
Astronomers working on TMT will have a full suite of scientific instruments at their disposal, so the telescope will essentially be able to be used to study anything and everything in the cosmos. But in terms of ushering in new discoveries, in broad strokes, TMT will be ideal for studying the origin of the universe and exoplanets.
Understanding the nature of the universe, how it – and by extension we – ended up here is a significant question for science and astronomy to try to unravel. TMT will take full advantage of its massive mirror to peer back in time and capture the faintest light from the earliest moments following The Big Bang. By observing how ancient stars and galaxies formed, it will advance our understanding of why things are the way they are, and inform what the forces at work in the universe are today. TMT will also help to fill in gaps about the structure of the universe and the role that dark matter plays.
In terms of exoplanets, TMT will have the resolution to directly image worlds orbiting other stars. Using spectroscopic instruments, astronomers will also have the ability to measure the composition of those worlds – and whether they could be hospitable for life.
Thirty Meter Telescope will perceive things that no other human-built technology has ever been able to see. In so doing TMT will help to answer two of the most fundamental questions of our existence: how did we get here and are we alone.
The next generation of discovery is just beyond the horizon today, but it’s exciting to know as a human that before long, we’ll have it in our sights.
As a Canadian, it’s exciting to know that my nation will play a significant role in those discoveries and the benefits that follow from being a leader in research and technology development.
I joined Jerry Agar on Toronto radio station CFRB Newstalk 1010 to describe TMT. Listen here:
Over the past week or so we’ve seen a few stories regarding wet bodies in our solar system.
First, there was news about water on Mars. Now the news wasn’t so much that there was water on Mars, since that’s been pretty well understood for a while now (thanks in large part to the rovers Spirit, Opportunity, and Curiosity), rather how much water there was – and it’s plentiful to say the least.
Mars with a vast Northern Ocean (NASA/Goddard Space Flight Center)
Using land-based infrared telescopes (the ESO’s VLT and NASA’s Keck), NASA was able to measure the hydrogen isotopes in Mars’ atmosphere. The results indicate that Mars one had 20 million cubic kilometers of water – more water than is in the Arctic Ocean here on Earth today. Astronomers are also currently suggesting that the Martian water was contained, mainly, in one large ocean surrounding the Red Planet’s north pole. It would have covered proportionally more of the planet’s surface than the Atlantic Ocean does here.
Nowadays on Mars it’s bone-dry, quite a bit different from ~4 billion years ago. Current estimates suggest that Mars’ ancient ocean contained about 6.5 times more water than what is currently observed in Mars’ polar ice caps, meaning that a great deal was likely lost into space as the Martian atmosphere thinned 2-4 billion years ago (though some water could still possibly be trapped in a permafrost layer).
The next news item this week is regarding Enceladus, an icy moon of Saturn. Now again, we’ve understood for a while that this moon had a sub-surface ocean of liquid water, trapped beneath an icy crust, but the news this week is tantalizing: the possibility of active hydrothermal vents in the moon’s southern ocean.
Hydrothermal activity on Enceladus (NASA/JPL-Caltech)
Announced just a couple days ago thanks to data from the Cassini spacecraft, astrophysicists have been able to pinpoint the origin of tiny particles of silica that the spacecraft had been detecting in space as it orbits in the area. And the origin appears to be the southern ocean of Enceladus, a 10km deep body of water. How the silica particles form is a chemical process that takes places when ocean water interacts with volcanic activity on the ocean floor.
Precisely the same process has been observed in only one other place so far: right here on Earth. And on our world, hydrothermal vents are teeming with life.
Jump ahead to today, and NASA announces, using Hubble data, that the largest moon in our solar system has a sub-surface ocean of liquid water of its own.
Ganymede, a moon of Jupiter, has been theorized to have a sub-surface ocean since the Galileo probe visited the area in 2002. Shifting magnetic fields were a major clue indicating the presence of water, though the data at the time was inconclusive. But now a novel idea has allowed a team of astronomers to make use of the Hubble Space Telescope to study Ganymede’s shifting magnetic fields from afar: patterns in the moon’s auroras.
An illustration of Ganymede’s auroras (NASA/ESA)
By understanding how different materials impact magnetic fields, and how auroras present themselves through those magnetic fields, the astronomers were able to understand Ganymede’s make-up by studying the auroras using Hubble. What they found is an ocean of water. (Edit: not only an ocean of water, but a large ocean. Ganymede could have more water in its salty subsurface ocean than Earth does in all our oceans combined.)
With all this in mind – and not to mention other wet worlds, like Europa – the solar system is starting to look a little more damp than it was once thought to be. And here on Earth at least, it is well understood that anywhere you can find water – in any form – you are virtually guaranteed to find life as well.
So how do these discoveries impact the prospects for finding life in our solar system beyond Earth?
On Mars, I’m not sure it changes much. It’s been understood that the planet was once wet, that it was wet for hundreds of millions of years (if not a billion or more), and that the environment was once life-friendly. This week’s discovery drives home the idea that there was plenty of water, but I don’t know that it’s a game-changer.
For Enceladus, this is a significant discovery. Adding in the fact that geysers have been previously detected with organic chemicals, this icy world now has to be considered one of (if not the most) likely places to harbour life in our solar system. As we understand life, it needs water and an energy source; Enceladus now seems to have both. Contemplating what might be swimming around in that alien ocean right now is an intriguing thought. (Maybe Enceladus leap-frogs Europa as the target for a robotic submarine mission?)
Ganymede? Add it to the list of worlds with liquid water that require more study. (I would similarly categorize Europa.) Questions abound as to the nature of their oceans, if there is any volcanic activity, do they cover the entire world, and could there be life?
Clearly we have some exploring to do.
Astronauts on board the International Space Station capture an image of the Space Shuttle Endeavour prior to docking during the mission STS-130 in February 2010 (NASA).
The year 2015 is poised to be a busy one for space exploration.
New Horizons arriving at Pluto is perhaps the biggest story in a number of years, and has certainly been a long time coming. Humanity exploring a new world (note I say world, not planet) in our own solar system is a notable event. New Horizons’ closest approach to Pluto will be on July 14, 2014 at 7:49:59 a.m. ET.
Ditto Dawn’s arrival at Ceres. The possibilities of what could be found there are very intriguing. Dawn is set to arrive in orbit of Ceres on March 6, 2015.
SpaceX makes the top three for me on account of what they’re going to be trying to accomplish this year in terms of reusable rockets (January 6 launch upcoming Tuesday is definitely one to watch). This is pushing new boundaries in terms of rocket technology. Watching the continued development of Dragon V2 is also significant.
Though along with SpaceX, I consider the ongoing expansion of private space flight truly noteworthy. It will reshape how we view space travel, and the number of people who can achieve it.
Long duration ISS stays are also something to watch, as much as anything because of how they fit into the puzzle that is humans one day reaching Mars.
There’s also a solar eclipse upcoming on March 20, 2015, and two lunar eclipses this year: April 4 and September 28, 2015.
Artist’s concept of the New Horizons spacecraft during its planned encounter with Pluto and its moon, Charon. The craft’s miniature cameras, radio science experiment, ultraviolet and infrared spectrometers and space plasma experiments will characterize the global geology and geomorphology of Pluto and Charon, map their surface compositions and temperatures, and examine Pluto’s atmosphere in detail. The spacecraft’s most prominent design feature is a nearly 2.1-meter dish antenna, through which it communicates with Earth from as far as 7.5 billion km away. Image Credit: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Harrison lives in Ottawa, Canada. He works in politics and is passionate about many things, including space and exploration. He's worked for a national news outlet, managing the digital products, writing news, and appearing on air to talk about science, technology, and politics. In his spare time he enjoys astronomy, scuba diving, flying airplanes, photography, and sports.