New planet-hunting camera produces best-ever image of an exoplanet | Hacker News Reader

New planet-hunting camera produces best-ever image of an exoplanet

news.stanford.edu

80 pointsbane21 comments

I don't know if this gets said enough, but it bears repeating: we are truly living in a golden age of astronomy. Some incredible things are happening.

In my opinion, we need to continue to bring the cost to Low Earth Orbit down by any means necessary, including railguns for non-human traffic. Low cost-to-orbit would dramatically speed up dozens of things, exo-planet imaging among them.

As much as I love human space travel and robotic exploration, I have to admit that exoplanet research and imaging is really where all the exciting stuff is going to happen. How much longer until we have an image of another Earth? Wonder what a space-based astronomical interferometer about the width of the solar system could image? And that's what? A 10-20B project? Imagine the change in the public's imagination a series of images of the countless other planets in the galaxy would bring.

I think you're extremely optimistic with that cost estimate. The total cost of the James Webb space telescope will likely end up around $10B... and that's a 6m or something infrared imager in LEO.

For a space-based interferometer mission, eLISA is a non-optical interferometer (for gravitatinal waves) with 1e6 km arms with a budgeted cost of 1.3B Euro. An interferometer needs to control spacing by a fraction of a wavelength, but for gravitational waves that's like 1e9 m. Optical light is 1e-7m. That's 18 orders of magnitude higher precision over a proposed 3 orders of magnitude larger baseline.

I think it's fair to say the cost of such a mission would be "out of this world", because we have no idea how to build it, and it's not the launch cost to LEO that's the problem.

> and that's a 6m or something infrared imager in LEO.

James Webb Space Telescope won't be in LEO, they'll fly it to the L2 Lagrange point: http://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Orbi...

Oh, you're right. My bad.

The hard technology in JWST had to do with the cryocooler, which was needed to cool the infrared detectors to just a few degrees Kelvin. (Of course IR is the whole point of the mission.). The cryocooler was unique in several ways, including sheer size and a complex routing throughout the spacecraft bus.

There is no basis to compare the hard technology in JWST to the hard technology in a space interferometer. They are two very different beasts.

> For a space-based interferometer mission, eLISA is a non-optical interferometer (for gravitatinal waves) with 1e6 km arms with a budgeted cost of 1.3B Euro. An interferometer needs to control spacing by a fraction of a wavelength, but for gravitational waves that's like 1e9 m. Optical light is 1e-7m

Could explain what you're saying here better? The LISA satellites will making measurements of changes in the million km distances between each other to an accuracy below 20 picometers.

This is such a good comment. It's amazing to think that, during our lifetimes, it is likely that we will see an image of another Earth-like planet outside our solar system. Lucky us.

The best image ever of an exoplanet is now 36 pixels :)

I wonder if we can apply Moore's law to this? Every 1.5 year the number of pixels doubles. So in 10 years it will be 3600 pixels, an in 20 years 360k. Another 10 and the resolution needs to be so high that you'd have to fly to it to take the picture :)

The "pixels" are misleading. It isn't pixels of an image of a planet, it's pixels of the point spread function of the diffraction limited smear of the planet. Increasing the resolution of that image isn't going to result in being able to resolve the planet itself, it'll just show a smudgy smeary point of light in greater detail. In order to actually resolve the planet into real pixels we'll need much larger telescopes, likely outside of Earth's atmosphere. And we're a long way off from that.

This. It would be easier to identify this sort of thing to a layman as '0.000001 pixels, blurred over 36 pixels due to lack of optical telescope power'.

does moore's law apply to astrophysics or optics ?

We can certainly derive a "law" analog to Moore's law about exoplanet resolving power, but I suspect it will be a much less reliable predictor than Moore's law.

What is interesting to me is that 36 pixels is also about the size of the best image we have of Pluto, a [formerly known as] planet in our own solar system.

Can someone explain to me how this planet can be 10,000,000 years old? Isn't that formation far too new for a star system that close? I would have expected such formation to be inside a nebula near the core of the galaxy.

Planets form all the time in all parts of the galaxy. Supernovae happen all over the place, with enough frequency that there are constantly new stars born with new planetary systems.

The Sun is orbiting inside the thin disk, within 3K light years of the galactic plane, where most of stars and most new stars reside (other than the center bulge or bar).

http://en.wikipedia.org/wiki/Thin_disk

Star ages can be estimated by their composition (older stars contain more helium), color (bluer stars live far shorter than redder stars), brightness for their given color (older stars burn brighter), activity (younger stars are more active, they flare more) and if they contain protoplanetary disks (a feature of very young stars).

Astronomers also use the HR diagram: http://en.wikipedia.org/wiki/Hertzsprung%E2%80%93Russell_dia...

Having a good measure of distance is important and there are various ways to determine that: http://en.wikipedia.org/wiki/Cosmic_distance_ladder

Serious question: Is there a difference between a planet and an alien planet, or is it just a bit of flair added to the title?

Pretty sure it's supposed to mean extrasolar in this context - a planet not in our own solar system.

It looks like you're right. After posting my question I clicked through to the GPI site (http://www.planetimager.org), which says the project is imaging and characterizing exoplanets. And, in case anyone else is curious, an exoplanet is a planet outside our solar system.

We changed the title to say "exoplanet" instead of "alien planet".

Since we have pretty awesome pictures of our own planet, it's clearly not meaning any planet. I guess it's true that "alien" could have referred to any other planet than Earth, but that wouldn't really be "planet hunting". But yeah, they should have written "exoplanet".

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