I like to say that we’re in the golden age of astronomy, learning things about the Universe
with a level of precision and resolution that previous generations of astronomers could
only dream about.
Imagine if you could show Galileo Galilei or Copernicus images from the Hubble Space
Telescope, or the mighty Keck Observatory.
They would blow their minds.
But I really think the true golden age of astronomy is right around the corner.
That’s because there’s a whole new class of observatories in the works right now which
are going to take us right out to the edge of the Universe in ways that would have seemed
impossible decades ago.
In the land of telescopes, bigger is better, and the big telescopes are coming.
Today we’re going to begin a two-part series of episodes all about the new supertelescopes
under construction.
In this first episode, I’ll talk about the enormous ground telescopes in development,
and then next episode, I’ll talk about the space-based telescopes in the works.
I’d like to thank Universe Today columnist Evan Gough for writing our original series
on the upcoming supertelescopes.
This video is based heavily on Evan’s work, so… thanks Evan!
Let’s get started.
Before I talk about the specific projects, I want to give you a sense of scale.
There are a few really large observatories around the world.
There are over a dozen telescopes with an aperture of more than 8 metres.
There are the Gemini North and South telescopes, the 4 European Very Large Telescopes, the
Subaru Telescope, the Large Binocular Telescope, the Southern African Large Telescope, the
twin Keck Telescopes in Hawaii, the Hobby-Eberly Telescope and finally, the Gran Telescopio
Canarias in the Canary Islands, measuring 10.4 metres across.
The Large Binocular Telescope is the equivalent of an 11.9 metre telescope, with two 8.4 metre
mirrors side-by-side merging their optics.
These are big.
Here’s bigger.
The first supertelescope under construction is the Giant Magellan Telescope located in
the dry mountainous Atacama desert in Chile.
This is one of the best places in the world to put a telescope, because it’s so dry
and clear, far away from any city lights.
In fact, several of the world’s largest telescopes are already located here.
The Giant Magellan Telescope was begun in 2015, and if all goes well, it should see
its first light in the early 2020s.
The observatory is based on a segmented design, with 7 separate 8.4 metre mirrors put into
an array.
The light from all the separate mirrors is merged together to act like a single larger
mirror measuring 24.5 metres across.
With this much raw observing power, it should have about 10 times the resolution of the
Hubble Space Telescope - but from Earth.
There are really big advantages to having a telescope on Earth.
As new instruments are developed, or hardware fails, you can just service the telescope
without needing to send a team of astronauts.
Space telescopes have a higher resolution in general, because they’re above the distortion
of the atmosphere.
But ground based telescopes partially overcome this using a technique known as adaptive optics.
They fire a laser into the sky that creates an artificial star.
The telescope then watches the distortions happening to the artificial star and physically
deforms the telescope’s mirror to counteract the distortions.
In order for Magellan to work properly, the 7 mirrors need to be aligned perfectly, with
a precise shape within a few hundred nanometers of each other.
The first mirror was cast back in 2005, and technicians took 6 years to polish it perfectly.
And then the other mirrors need to match it perfectly, positioned within incredibly tight
tolerances.
Once constructed, Magellan will be a general purpose telescope used to observe stars, planets,
galaxies and other phenomena across the Universe.
And here’s the most amazing part.
It’ll be capable of directly observing extrasolar planets from the ground.
The actual planets.
Until now, this feat was only possible by the most powerful space-based telescopes.
And this is why I’m so excited about Magellan.
But just you wait, it gets even better.
The next telescope under development is the Thirty Meter Telescope.
Unlike the GMT, the 30-Meter Telescope will appear as one huge primary mirror, and will
be, you guessed it, 30 metres across.
But if you look up close, you see that the mirror itself is actually made up of 492 separate
1.4 meter segments in a hexagonal pattern.
Added up, this telescope will provide 10 times the resolution of the Keck Telescopes, and
more than 144 times the power of the Hubble Space Telescope.
One of the advantages of the TMT will be its ability to resolve objects where are very
close together.
It’ll be able to see distant galaxies, planets orbiting stars, binary stars and other objects
where this technique is important.
As with the GMT, it’ll have adaptive optics, distorting its primary mirror based on turbulence
in the atmosphere.
But it’ll also have active optics, compensating for wind, temperature and other stresses on
the telescope.
It’ll have a wide range of wavelengths of light that it can see the Universe with, from
near-infrared, visible and into the ultraviolet.
Very similar to the capabilities of the Hubble Space Telescope.
Now, I know what you’re saying, gimmee this telescope!
But there’s been a bit of a controversy over its construction.
The observatory was originally planned to be build on Mauna Kea, Hawaii, with the rest
the Hawaiian observatories.
Protesters stopped construction in 2014, snaring the development in the courts.
In the end, the courts sided with the local peoples, saying that the TMT hadn’t properly
followed due process before beginning its construction.
Earlier this year, the TMT announced that they would be locating the telescope in the
Canary Islands, nearby the largest telescope in the world.
At this point, there’s no concrete date for when the telescope will finally be completed.
Next up, the European Extremely Large Telescope, or E-ELT.
Kudos to the Europeans for really nailing telescope names.
XKCD knows what I’m talking about, I can’t wait for the Despair Telescope.
Time to go even bigger.
The E-ELT is also under construction in the Atacama Desert in Northern Chile.
This scope will have a 39-meter primary mirror.
Needless to say, once constructed, it’ll be the largest telescope on Earth.
If all goes well, it should receive first light in 2024.
Like the TMT, it’ll be made of segment; 798 individual little mirrors which can be
individually aimed or moved to account for ground conditions as well as atmospheric turbulence.
Unlike other observatories the E-ELT will have a more complex set of secondary optics,
which should give it better image quality over a wider field of view.
By being an even bigger, more sensitive telescope, the E-ELT will be capable of viewing extrasolar
planets even closer to their stars.
It’ll also be watching the formation and evolution of planetary systems and even precisely
measure the acceleration of the expansion of the Universe thanks to dark energy.
But here’s the most exciting part.
This telescope will be brought into the search for life in the Universe.
To directly image the atmosphere of distant exoplanets to find out if they have signs
of life on them.
Three cool observatories, but I’ve saved the best for last.
And I’ll get into it in a second, but first I’d like to thank:
Ben Holden-Crowther Ray Bingham
Infinite123Lifer
And the rest of our 760 patrons for their generous support.
If you love what we’re doing and want to get in on the action, head over to patreon.com/universetoday.
If you’ve watched enough of my videos, you know there’s a telescope coming that has
a very special place in my heart: the Large Synoptic Survey Telescope.
Unlike the rest of the supertelescopes, it’ll have a main mirror that’s merely 8.4 metres
across.
That doesn’t sound like much compared to the 30-meter+ sizes I’ve been throwing around.
But for what the LSST lacks in size, it makes up in speed.
This telescope, also due for construction in Chile will be capable of photographing
the entire visible night sky every few nights.
With its wide field of view, it’ll be capable of capturing 3.5 degrees of sky in a single
picture - 50 times the area of the full Moon - at a level of sensitivity that matches other
world class telescopes.
In other words, it’ll capture image after image of the same region of the sky, looking
for things that change over the course of several nights: supernovae, asteroids, comets,
and other transient objects.
It’ll produce a catalog of 40 billion objects, and how how they change over time.
Online catalogs, like the Sloan Digital Sky Survey, are enormously important for astronomers.
The LSST will create a detailed catalog of the night sky, with the added dimension of
time.
Did you discover a supernova, look back through the LSST data to find the star before it exploded.
It’s expected that LSST will find the vast majority of dangerous Near Earth Asteroids
all on its own.
It’ll catch the Universe doing things when we weren’t looking.
And that’s the part that I’m most excited about.
The massive amount of data pouring out of the LSST will be available to anyone with
an internet connection, and the ability to run database queries.
The public will have access the same moment the scientists do.
Of all the supertelescopes, LSST is coming first.
It should see first light in 2021, and begin its first 10 year run in 2022.
Image being able to watch a movie of the southern skies over the course of 10 years, and see
every supernova, asteroid, comet and more.
Starting in 2021, everything changes.
The new golden age of astronomy begins.
LSST sees first light, followed by Magellan and the Extremely Large Telescope and eventually
the 30-Meter Telescope.
I can’t wait to hear what they discover, and I’ll let you know as soon as I find
out.
Well, which of these telescopes are you most excited about?
Do you agree with me that we’re about to really enter the golden age of astronomy?
I’d love to know your thoughts in the comments.
This wraps up part 1, where we talk about our ground-based telescopes.
In our next episode, we head to space and see what observatories are in the works to
see the Universe from a vantage point outside our Earth’s atmosphere.
That’s next time.
Time for your playlist.
Let’s start with a video about the Giant Magellan Telescope, and the challenges of
building a telescope this big.
A video about the Thirty Meter Telescope.
Another about the European Extremely Large Telescope, and a video about the Large Synoptic
Survey Telescope.
I want to wrap this up with our very own Weekly Space Hangout where I interview Dr. Meredith
Rawls from the Large Synoptic Survey Telescope.