Tag Archives: Telescope

All about the Thirty Meter Telescope (TMT)

8 Apr

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).

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).

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).

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 (labeled Sgr A*) with adaptive optics. (Source: Keck Observatory and the UCLA Galactic Center Group).

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).

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:

Intuition gives way to data in exploration of the Cosmos

2 Mar

data-intuit

Only the most anthropocentric among us would seriously argue that Earth, as part of a solar system, is a godsend.

Especially nowadays.

For me, it always made sense intuitively that our solar system is one among many – just as our star is one among many, or indeed our planet is one among many just in our solar system.

We’ve known for a while that our Sun is one amongst, literally, billions in the Milky Way alone. Thousands of years ago though this concept was intuition, and postulation. A lot of ‘what if?’ type statements were made about our Sun, in comparison to the twinkling lights of the night.

“What if we’re just a lot closer to this one, than to others, so it looks bigger and brighter?”

“What if it’s actually not all that different from others?”

Though there was no way to confirm these ideas – even if intuitively they did make a world of sense.

Through the advent of technologies – namely telescopes, invented roughly 400 years ago – data would eventually be provided to confirm the intuition that our little Sun was in fact quite a bit like all those stars that surround us at night.

(Of course to be accurate, the Sun is also dissimilar from many stars in terms of size, temperature, age, and so on — just as Mercury and Jupiter hold some traits in common, they are of course dissimilar in others.)

The Milky Way (Credit: A. Fujii / NASA)

The Milky Way (Credit: A. Fujii / NASA)

As time marches on, we find that in our solar system there is also a diversity of worlds: planets, moons, asteroids, comets – whatever classification you choose, there’s a multitude of those other bodies out there.

Again through technology – and again, namely telescopes – we’re able to confirm ideas that intuitively made sense to people of ages past: what if those wondering stars are other worlds?

In fact the word ‘planet’ derives from the Greek ‘asteres planetai’ – wandering stars – as the paths of the planets appears separate against the backdrop of the star field in our night sky.

Around the same time that we confirm there are other worlds around our star, folks start to wonder ‘what if those stars have planets, like ours does?’

It makes sense intuitively – just as the concepts of other Suns in the galaxy and worlds in our solar system makes sense.

What’s been lacking though is the technology to confirm this intuition – since let’s be honest, intuition alone is a very lousy way to do science.

We need data to confirm the hypothesis.

The first exoplanet – or extra-solar planet, aka a planet orbiting a star other than the Sun – was discovered in 1992. That’s only 22 years ago.

And in fact that 1992 discovery was of planets orbiting a pulsar. The first discovery of an exoplanet orbiting a main-sequence star (something loosely like the Sun) was in 1995 – not even two decades ago!

So on one hand, it might have been forgivable for people to argue that our solar system is unique. There had been, after all, no data to argue otherwise.

On the other, since the mid-90’s, there have been different techniques to detect exoplanets.

Though it wasn’t until 2009 that the rock star took the stage: Kepler.

(if you want to read all about the Kepler mission, go here – those details aren’t what this article is about)

With the Kepler mission taking centre-stage in our planet-hunting endeavour, we were finally able to take the first steps in confirming something that makes sense intuitively: many (if not most) other stars have planets orbiting them, just as ours does.

Exactly how many planets each star has, exactly the nature of those planets orbits, exactly the composition of those planets – and many other details – continue to be open questions in most cases. Though it’s worthwhile to note that in some examples, perhaps a dozen, we have a pretty good understanding of the answers to those questions.

Should it be surprising that we don’t have all the answers? Of course not. We have only confirmed that these things exist in the first place in the last couple decades.

Though as Kepler data continues to be unravelled (even if Kepler’s prime mission is kaput), I expect we will continue to hear announcements like the Kepler 715 release.

There are planets out there everywhere – and lots of them.

Their makeup is as diverse as the makeup of our solar system.

But now that we have data to confirm the exoplanet intuition, we need data for next big intuition: life.

And just has happened historically, we’ll start in our own solar system with Mars.

We have been investigating Mars from afar for hundreds of years. Over the last few decades we’ve been investigating it close-up. We’ve confirmed the presence of water. We’ve confirmed a hospitable environment (at least historically).

What’s next?

It’s time to go to Mars and search directly for life.

This search will primarily be one for ancient life, though it’s not out of the question that some microbes could exist underground near a water supply today.

Once again, this is an issue where it is intuitively plausible that Mars was home to life. We know the conditions were right, so why not?

But this is a big question, and again intuition isn’t enough – we need data.

To this end, the ESA’s Mars mission slated ford 2018 will have a direct search for life as it’s goal. NASA’s next large Mars rover is set for 2020.

I do, openly, speculate that this is another case where intuition will eventually be confirmed by data (whether it’s within the next few years or not though is harder to guess – Mars is a pretty inhospitable place now, and so evidence of past life might be hard to find – if it is there at all).

Speculation aside though, data can confirm for us that Earth is simply one planet amongst hundreds of billions – if not more.

This is a reality that may take some time to sink in, but it is an undeniable truth.

Just as it is equally true that the Earth is round, that we orbit the Sun, and that the Sun is but one amongst a vast ocean of stars.

Space Telescopes abound!

4 Jun

The Hubble Space Telescope (2009). Source: hubblesite.org

Last night after work I was having a beer with a colleague, and amongst various other things, we ended up talking for a few minutes about how long the Hubble Space Telescope will last. Specifically, we were discussing whether it will remain useful until 2018, which is when NASA is currently* planning on having the James Webb telescope ready. With the Space Shuttle fleet now retired, NASA doesn’t have any ability to perform maintenance on Hubble, replace parts, or make any required adjustments – so its days are numbered. At some point a gyro will fail, its alignment platform will lose its precision, and the imaging CCD sensors will have pixels die. It’s inevitable, but my colleague and I ended up agreeing that Hubble will likely remain functional in some way (though perhaps not in 100% condition) for the next six years.

* = I say “currently” because the James Webb telescope is presently four years behind schedule (and drastically over budget) so it is impossible for me to say confidently that 2018 will end up being the actual date that it’s ready.

Then today, we read the news that there are two telescopes (better than Hubble) just sitting around collecting dust in Rochester, NY.

(if you didn’t read the news, check it out here: Washington Post)

It sounds almost unbelievable, but it’s true. The US Department of Defence has gifted two better-than-Hubble space telescopes to NASA.

And before we get into these two new ‘scopes, let’s take a little look back at the Hubble Space Telescope, which has allowed us to peer deeper into the cosmos than we ever have before.

The Hubble telescope is named after Edwin Powell Hubble, who was an astronomer in the early 20th century. Around 1920 he made the remarkable discovery that there were other galaxies beyond our own – a fact that we take for granted today (and of course he did other things too). Shortly after that, in the mid-1920s, the idea came about (from a German named Oberth) that it would be a good idea to put a telescope in space. Various ideas and designed followed over the next 30-40 years. Some satellites were launched (NASA launched the Orbital Astronomical Observatories in the 60s), however nothing yet on the scale of Hubble (which at the time was called the “Large Space Telescope”). In the mid 1970’s NASA started work on the Space Shuttle, which would be the new vehicle that would carry equipment into space – and allow (for the first time) service-calls while in orbit. Then, in 1977 the US Congress approved funding for one of the most sophisticated satellites ever built. This satellite was, of course, Hubble. Skip ahead a few more years to 1985, and Hubble was ready for launch. But in 1986 disaster stuck, with the loss of Space Shuttle Challenger, grounding the entire Shuttle fleet for two years and pushing back the launch of Hubble to April 24, 1990.

Since then? Well, the results speak for themselves:

And today, I repeat for a third time, the US Department of Defense (DOD) has gifted two telescopes – better than Hubble – to NASA. These two new telescopes were apparently built in the late 1990s by DOD contractors. Their mirror (the main component in determining the power of a telescope) is the same size as Hubble’s at 2.4m however their optics are much improved, including a field of view 100-times that of Hubble. These two new telescopes also have a maneuverable secondary mirror that Hubble lacks, allowing for higher-precision focusing. The design of the new telescopes also allows for a broader set of instruments to be installed.

The fact that these two new-found telescopes are better than Hubble shouldn’t be terribly surprising. When Hubble was designed and built, it was absolutely state of the art. But it was also designed and built in the 1970s and 80s. These two new telescopes were designed and built in the mid/late-1990s – and technology progressed a lot over those 20-30 years.

The surprising bit to me is two-fold: 1: The DOD had these two telescopes sitting in a warehouse in Rochester, NY collecting dust; and 2: The DOD, by openly gifting these telescopes to NASA, is willing to face intense scrutiny (and rightfully so) regarding what else they have sitting around collecting dust and how much money they have spent/are spending on projects like this (big kudos to the DOD for a willingness to bite that bullet, in the interest of helping out NASA, since the DOD could have just as easily scrapped these two beauty’s quietly).

Now onto the practical part of this story: NASAs budget and space lift capabilities, or lack thereof.

The two new telescopes need instruments. They need staff support. Scientific missions. Office space.

After all that, they need to be launched into orbit and deployed.

NASA simply does not have the capacity to do any of this, and likely won’t for another decade or so. Now NASA has undergone budget cuts lately, but to be fair a lot of this pain is self-inflicted: their previously referenced James Webb telescope has incurred such staggering budget overruns that it has forced the cancelation or delay of numerous NASA scientific missions.

NASA estimates that it could be 2024 until they have the ability to launch one of these new telescopes (launching the second one wasn’t even considered), unless money is no object, in which case they might be able to do it by 2018-2020 – which is still a rather long time line.

My solution? NASA should sell one of the new telescopes.

I’d be quite certain that either another space agency (European Space Agency, Japan Space Agency) or a commercial enterprise (SpaceX) would love to get their hands on one of these telescopes.

SpaceX’s Dragon docks with the International Space Station (May 25, 2012). Source: NASA


The benefits of selling one of them are numerous: NASA would get a cash injection right now that it desperately needs; the likelihood of both these telescopes being put into service would be greatly increased; the idea of creating some competition in the ‘discovery industry’ is a good one; one of them would probably end up in space faster than 2018-2024 that NASA projects; and by engaging another agency or company, NASA can help to inspire others to make amazing discoveries and help us to learn about the Universe and how we got here.

And of course NASA will still have the other telescope (and James Webb) to outfit, launch, and operate as their budgets allow.

I do expect the DOD would have something to say if NASA wanted to sell one of these new telescopes (it could very well be part of an agreement that NASA cannot sell them) as some of the design and technology inside is classified – and I’m sure the DOD would be hesitant to have outsiders crawling around inside them. Hopefully this problem can be overcome.

Whatever happens with these telescopes, in the very near future when I wake up tomorrow, I will live in a world where there are two more space-telescopes than I knew about yesterday – and that’s a good thing.