How Do New Kinds of Telescopes Make New Discoveries? with Astrophysicist Michael Shara

[Zoom in on high-definition telescope observation of stars in space.]

MICHAEL SHARA (Curator, Division of Physical Sciences): Astronomers are always looking for new phenomena.

[Michael Shara speaks to camera from an office in the Museum with framed artists’ depictions of space on the wall behind him, and a telescope on the table next to him.]

SHARA: We have a catalogue of about 100, 150 different things in astronomy.

[As Shara lists astronomical objects, a telescope observation of each appears next to him in a split-screen.]

SHARA: Red giant stars, sun-like stars, white dwarfs, neutron stars, black holes, spiral galaxies, elliptical galaxies, dwarf galaxies, giant galaxies, and so on.

[A sequence of detailed images from telescope observations of stars and celestial objects.]

SHARA: But we haven’t found everything there is. There are classes of objects, and we know this with certainty, that exist in astrophysics that we have not yet found. Now, how do you find something absolutely brand new?

[Time-lapse footage of ground telescopes part of the European Space Organization’s Atacama Large Millimeter Array taking observations of the night sky in the Atacama Desert in Chile.]

SHARA: The bottom line is you find new things by building new kinds of telescopes. 

[Museum Logo appears followed by text on screen: “How Do Novel Telescopes Make New Discoveries? with Astrophysicist Michael Shara”]

[Shara speaks to camera.]

SHARA: I’m Michael Shara, curator of astrophysics at the American Museum of Natural History.

[Computer visualizations of binary star systems.]

SHARA: I’ve always been interested in the structure and the evolution and the births and deaths of binary stars. 

[The sun shines in the sky above the ocean as seen from Earth, followed by a time-lapse of telescope images of the sun spinning in space.]

SHARA: The sun is a single star, living in isolation for the last four and a half billion years.

[A telescope image of two binary stars in space.]

SHARA: But about half of all stars are born with a companion.

[A computer visualization of a star expanded into a huge ball of fiery gas towards the end of its life cycle.]

SHARA: And as stars evolve, as they burn up the hydrogen in their cores, they tend to swell in size. And so stars that initially aren’t interacting with each other do start to interact, and that leads to a fascinating set of phenomena including nova explosions, supernova explosions, and other wild and crazy things that stars do.

[Shara speaks to camera and smiles.]

SHARA: That’s what I study. 

[Computer visualizations of a small white/blue star syphoning material from a larger yellow/red star.]

SHARA: Nova explosions occur in binary systems where one of the stars is just like the sun, but its companion is the corpse of a star. An older, more massive star that has turned into a tiny earth-sized object that starts to cannibalize matter from its companion.

[Computer visualization of a large, fiery nova explosion in space.]

SHARA: Novae brighten to a million times the brightness of the sun, it doesn’t lead to the destruction of either star.

[Computer visualizations of various causes of supernovas.]

SHARA: Supernovas are the destructions of stars, the deaths of stars. It can be a single, very massive star that collapses under its own weight. Or it can be a binary star, where you have one star dumping matter on to another one so fast that it collapses. Or perhaps two stars merging to form an object that’s too massive to hold itself up 

[Visualization of a large, fiery supernova explosion in space.]

SHARA: They blow themselves up, destroy themselves, eject themselves into space at five, ten, even 20 percent the speed of light…

[Artist rendering of a neutron star, followed by a visualization of a black hole rotating and moving through space.]

SHARA: …and they leave behind either a super dense neutron star, or in the most extreme case, a black hole.

[Hubble Telescope image of a supernova seen from across the cosmos.]

SHARA: These deaths of stars, can be seen halfway or more across the universe via the Hubble Space Telescope. 

[NASA footage of the Hubble Telescope flying through space, as seen from a camera mounted to Hubble.]

SHARA: The Hubble Space Telescope remains one of the two most powerful telescopes ever built.

[Footage of the James Webb Telescope being completed in a NASA facility.]

SHARA: And of course the Hubble Telescope has now been joined by the James Webb Space Telescope operating in the infrared part of the electromagnetic spectrum, whereas Hubble is a visible and ultraviolet telescope. 

[Split-screen comparisons of observations made by Hubble and Webb of the same objects in space, showing the differences in their observations in terms of color, texture, and details achieved and omitted by each.]

SHARA: And so these two telescopes work in beautiful synergy, sometimes looking at the same object or the same class of objects to understand what is going on. 

[SHARA speaks to camera.]

SHARA: Over the last several years, I’ve been really fortunate to be involved in a brand-new project in astronomy…

[A photograph of a new kind of telescope, much smaller than any of the telescopes shown previously, consisting of six lenses mounted together.]

SHARA…called the Condor Telescope Array.

[A sepia-tone photograph from 1878 showing Astronomer Maria Mitchell instructing six female students in long, dark dresses, using small thin telescopes on the lawn at Vassar College. This is followed by a black-and-white photograph of a man sitting in the observing chair of a very large telescope built in the early 1890s.]

SHARA: Up until around 1900, all telescopes were refractors. Telescopes that operate very much like a pair of binoculars.

[An animation of a refracting telescope, showing light entering, passing through a lens, and landing on the part of the telescope where an observer would place their eye.]

SHARA: A lens, which captures light, it focuses it on to an eyepiece. 

[Shara speaks to camera.]

SHARA: By around 1900, astronomers ran into a hard limit.

[A series of black-and-white photographs of large refractor telescopes.]

SHARA: You can only make a refracting telescope about one yard across. If it gets any bigger, it starts to sag under its own weight. So you can’t keep the image focused. And so astronomers basically discarded refractors and started working with reflecting telescopes only. 

[A black-and-white photograph of a large reflecting telescope, circa 1912.]

SHARA: A reflecting telescope is a mirror. And that curved surface of a mirror captures incoming light, and brings it to a focus.

[An animation of a reflecting telescope, showing light entering the telescope, bouncing off of a mirror at the back of the telescope, then bouncing off a smaller, angled mirror about halfway up the telescope, and landing on the part of the telescope where an observer would place their eye.]

SHARA: And today, there are telescopes that are 10 times the size of the largest refractor ever built.

[Video of the European Space Organization’s Very Large Telescope in Chile, taking up an entire large room, with a very large mirror at its center. Text-on-screen labels the mirror as “mirror/light-collecting area”.]

SHARA: But they have 100 times the light collecting area. And so they’re vastly more sensitive than any refractor ever built. 

[Shara speaks to camera.]

SHARA: About 10 years ago, a group of astronomers realized that, hmm, it’s true that we can’t compete in terms of collecting area to be able to see faint stuff with refractors, but we can buy lots and lots and lots of refractors in the form of telephoto lenses right off the shelf. Very cheap. 

[A photographer looks through the eye hole of a digital camera with a long, telephoto lens, like those that would be seen in sports or nature photography.]

SHARA: And in the last five years…

[A close-up of a smart phone camera followed by footage of friends taking pictures of each other with their phones.]

SHARA: …the same kind of camera that’s used in your cell phone, have become big enough to become competitive with the cameras which have been the norm in astronomy for the last 40 years.

[A side-by-side shot of the telephoto lens and closeup of the cellphone camera.]

SHARA: When you combine these two kinds of technologies together, it turns out that you can see the very faintest things in astronomy, what we call “low-surface-brightness objects” better than you can with reflecting telescopes. 

[Two telescope observations of collections of stars are labelled as “low-surface-brightness galaxies.]

[A video of the previously-seen Condor telescope, six long lenses mounted together, rotating as a unit on a rooftop.]

SHARA: And there is now a Condor Telescope Array, six refracting telescopes, up and working in New Mexico. I’m really fortunate to be part of it.

[A photograph of the night sky filled with innumerable stars as seen from the Atacama Desert in Chile.]

SHARA: We’ve just found the funding to build a copy of it in Chile up at 18,000 feet in the Andes at one of the most superb astronomical sites in the world.

And these two arrays of telescopes are going to allow us to survey the entire sky, the northern and the southern hemisphere…

[An image taken by the James Webb Space Telescope showing details of supernova remnant Cassiopeia A, followed by a image taken by the Condor Array Telescope of light emitted by a supernova. There are clearly differences in the ways the different telescopes capture visual information.]. 

SHARA: in particular narrow-band filters that let us get rid of all of the extraneous light and focus on the light emitted by diffuse gas ejected from novas and supernovas.

[A computer visualization of dark matter.]

SHARA: And maybe even the filaments of dark matter that run through the universe.