"How do they take pictures of exoplanets?" "How do they know that planet has water?" (VIDEO)

This video could be called "On the Hunt for Exoplanets" or something. It is well put together and answers common questions in a way most everyone can understand.

The hunt for exoplanets, planets around stars other than our Sun is a topic of fascination on this forum and was discussed at length in this week's episode of ATS Live (Episode 200).

As someone who is currently studying this subject and related ones on a daily basis I always try to keep an eye out for things that make it easier to understand what's going on and most importantly, answer frequently asked questions on the topic.

To that end, I came across this video a little bit ago and it seemed perfect for an ATS post in that it is fairly short (under 9 minutes) and answers key questions that often come up when discussing stories about exoplanets such as how a planet around another star can be photographed or how we can determine what a planet many lightyears from Earth is made up of.

As new space missions devoted to studying these worlds around other stars take shape, new powerful ground bases observatories are being constructed while more sophisticated instruments based on new electronics and optical techniques have given old existing telescopes a new place in the hunt.

The Palomar Observatory on Mt. Palomar in California was constructed in 1928.

Charles Lindberg had just been awarded a medal for crossing the Atlantic in an airplane, Amelia Earhart repeated the feat the same year.

The first commercial television station in the US begins operation

The first color TV transmission was demonstrated in Britain.

Mickey and Minnie Mouse made their first appearance.

US Congress approves the funding to build Hoover Dam.

James Earl Ray, Maya Angelou, Hosni Mubarak, Hendrik Lorentz, Fats Domino and Shirley Temple were all born.

Yet Palomar Observatory has successfully remained relevant and today stands at the forefront of exoplanet research through super advanced electronics and adaptive optics systems.

As NASA's Kepler satellite is reactivated in its K2 mission we can expect a lot more stories about exoplanets in the news through 2014 and beyond. As we both increase the number of known worlds and our detail of knowledge about what they are made out of as well as what might reside on them its time to learn a bit about some of the basic stuff that is being done in the area of Direct Imaging of exoplanets.

I was shocked that there were some people on ATS who had no idea we'd already taken images of some of these planets.

The remarkable thing is that this typically is not done with something like Hubble but by ground based telescopes including the ones at the 86 year old Palomar observatory.

If you ever wanted a behind-the-scenes look at what goes on in an observatory as exoplanet researchers seek to obtain images of distant worlds or simply want to know how it is all done then grab a cup of coffee and watch this video:

reply to post by JadeStar


I thought they just inferred a planet's presence by observing the distortion around the star. To actually produce an image of a world i think we would need to be within its companion solar system or relatively close.

reply to post by JadeStar


Nice JadeStar s&f

reply to post by JadeStar


Such a great video..I always wondered how they actually did that....very cool...and to think we probably are only 10-20 yrs away from some new tech that really lets us see much much more...

andy06shake
reply to post by JadeStar

 

I thought they just inferred a planet's presence by observing the distortion around the star.

There are a number of techniques used to discover these planets. The video I posted focused on the most recent technique called Direct Imaging.

It was something we could not do 15 years ago. It's however one of the most useful as we can learn a lot more about the planets if we can actually analyze the reflected light from their atmospheres.


The other techniques are:

Radial Velocity - Also called the "wobble" technique. This was how the first exoplanets were discovered by looking at the wobble of a star as a planet tugged on it. Kinda like how your body moves if you swing a yo-yo above your head. As the planet orbits the star the star moves towards or away from us. The light from the star becomes redder or bluer as a result (This is called the Doppler shift which is like a train whistle as a train moves away from you, it gets lower in pitch). This motion can be detected now at very fine levels of detail.

Transit - This is the technique which Kepler uses, but was first demonstrated on a ground based telescope. It basically looks at a star measuring the stars brightness. If a planet passes between us and the star the star's light dims a tiny but measurable bit. If they see this happen on a regular basis then that confirms a planet is in orbit above a star.

Microlensing - Gravitational microlensing occurs when the gravitational field of a star acts like a lens, magnifying the light of a distant background star. This effect occurs only when the two stars are almost exactly aligned. Lensing events are brief, lasting for weeks or days, as the two stars and Earth are all moving relative to each other. More than a thousand such events have been observed over the past ten years.

If the foreground lensing star has a planet, then that planet's own gravitational field can make a detectable contribution to the lensing effect. Since that requires a highly improbable alignment, a very large number of distant stars must be continuously monitored in order to detect planetary microlensing contributions at a reasonable rate. This method is most fruitful for planets between Earth and the center of the galaxy, as the galactic center provides a large number of background stars.

Astrometry - This method consists of precisely measuring a star's position in the sky and observing how that position changes over time. This was the first technique that was heavily used to try to find planets, particularly in the 1980s but was completely unsuccessful because as it turned out, its the hardest technique to find planets with, next to direct imaging. Especially from Earth. It was popular because of its success in characterizing astrometric binary star systems. In 2002, the Hubble Space Telescope did succeed in using astrometry to characterize a previously discovered planet around the star Gliese 876. The recently launchedspace-based observatory GAIA, will find thousands of planets via astrometry.

To actually produce an image of a world i think we would need to be within its companion solar system or relatively close.

Nope, just need to block out the light of the star through some method. Either a starshade (also called a coronagraph) or using interferometry.

Google "Terrestrial Planet Finder" and "Project Darwin". Both have been cancelled but both would have been able to get images of Earth sized worlds a few pixels wide (enough to analyze their starlight for composition, land mass/ocean distribution and look for biomarkers such as oxygen and ozone which could be strong indicators of life.)

Our best bet for this is now the massive European Extremely Large Telescope (E-ELT) being constructed in Chile and an as yet unfunded NASA space telescope called the New Worlds Explorer.

reply to post by JadeStar


Thanks for the info Jadestar, will give the video a look when i return home.

reply to post by JadeStar

That was a good video, simple enough to be understandable but still informative. I think there are other techniques for finding exoplanets, but they don't reveal as much information about composition as that method.

VERY nice and informative video . It must be so cool to do this kind of "job" on a daily basis

reply to post by JadeStar


Finally got to see the video, well you live and learn I suppose. I'm amazed at the techniques these people seem to be able to apply to exoplanet detection I thought they just seen the wobble but they are actually managed to resolve images of distant worlds!

I'm impressed to say the least!

scientists work out way to determine atmospheric pressure on exo planets:

www.sciencedaily.com...

Astronomers at the University of Washington have developed a new method of gauging the atmospheric pressure of exoplanets, or worlds beyond the solar system, by looking for a certain type of molecule.

And if there is life out in space, scientists may one day use this same technique to detect its biosignature -- the telltale chemical signs of its presence -- in the atmosphere of an alien world.

Understanding atmospheric pressure is key to knowing if conditions at the surface of a terrestrial, or rocky, exoplanet might allow liquid water, thus giving life a chance.

andy06shake
reply to post by JadeStar

 

Finally got to see the video, well you live and learn I suppose. I'm amazed at the techniques these people seem to be able to apply to exoplanet detection I thought they just seen the wobble but they are actually managed to resolve images of distant worlds!

I'm impressed to say the least!

edit on 4-3-2014 by andy06shake because: (no reason given)

It is impressive.

It's the march of technology paired with human ingenuity and endeavor.

5 years ago we could NOT have done this with such a small, earth based telescope.

Today we're doing it on a 5.1 meter telescope with an observatory that is 86 years old using state of the art electronics and optics!

stormbringer1701
scientists work out way to determine atmospheric pressure on exo planets:

www.sciencedaily.com...

Astronomers at the University of Washington have developed a new method of gauging the atmospheric pressure of exoplanets, or worlds beyond the solar system, by looking for a certain type of molecule.

And if there is life out in space, scientists may one day use this same technique to detect its biosignature -- the telltale chemical signs of its presence -- in the atmosphere of an alien world.

Understanding atmospheric pressure is key to knowing if conditions at the surface of a terrestrial, or rocky, exoplanet might allow liquid water, thus giving life a chance.

edit on 4-3-2014 by stormbringer1701 because: (no reason given)

I know those people! That's my school.

lol. well i din't see anything on it but i couldn't find the other planet related threads so i put it here.

electronic optical camera astronomy takes off with pictures from beta (groan) pictoris.

www.sciencedaily.com...