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Hubble Discovers a Hundred New Planets
Spudley writes "The BBC is reporting that the Hubble Telescope has discovered over a hundred new exoplanets - a number which almost doubles the total known. Apparently they are also expecting to be able to analyse the atmospheres of up to 20% of them. The discovery will be confirmed within the next seven days."
None. If you RTFA, you'll see that the method used is to measure a dimming of a star, which can (but doesn't have to) be from a planet passing in front of it. For this to be measurable over the natural fluctuations of a star, the planet will have to be a giant.
Of course, the precense of one or more giant planets in a system increases the chance of habitable planets, as the giants acts like vacuum cleaners, keeping the smaller ones relatively undisturbed.
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The Drake Equation.
So how many of those 200-odd planets that we know of are capable of supporting carbon-based life? You crunch the numbers . . .
Actually, an other space telescope will be brought in space a few years after hubble 'dies', and it will be a lot better. The shuttle incident really caused problems in space explorations. The shuttles are all still locked on the ground (in pieces) and when they will fly again, the ISS will be their only destination. This is the reason why hubble won't be repaired, there is simply no shuttle going that way and they just don't consider the repair is worth a $500 million launch.
But it's not too bad since there will only be a 4 year gab (or so) between both satelites.
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Hopefully the upgrades will be good enough to complement the James Webb Space Telescope scheduled to launch in 2011. I can't wait to see if they redo "deep field" picture with this, it would be truely stunning.
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You can also detect planets by watching the way the star dims slightly when it's eclipsed. You can only detect really big planets this way; you wouldn't notice the transit of Venus from that far away.
But once you've found a planet that big, you can look even more closely and see what color changes you observe during the dim period. You can chalk that up to wavelengths of light absorbed by the planet's atmosphere, which you can use to hazard a guess as to what the planet's made of.
In all likelihood it's pretty much the same as Jupiter, which is to say pretty much like the sun itself: mostly hydrogen and some helium. But you might be able to detect faint signals of nitrogen, oxygen, maybe some carbon, and perhaps a bit of ammonia. The ratios of hydrogen to helium will suggest a lot about the way the planet was formed.
If the new telescope did everything that Hubble does, then I wouldn't mind.
However, the new telescope won't see in the visible spectrum like Hubble does.
This makes the new telescope less interesting to me.
*sigh* back to work...
I believe the first exoplanet was discovered in 1996, by Marcy and Butler, around 70 Virginis
The up to date list (minus these recent 100) can be found at exoplanets.org
This is incorrect, probably based on a misreading of this quote: "If this is confirmed, in seven days we will have doubled the number of planets known in nine years."
The article states that Kailash Sahu, the astronomer who made the discovery, did so during an observation period of seven days. According to the director of the Space Telescope Science Institute, they don't expect final results until September or October.
Whats more, with the advances made since the Hubble was made, ground based telescopes such as the VLT have nearly the same resolution as the Hubble and is much easier to service, so there is much less of a need for a space telescope
A minor correction: VLT and adaptive optic systems allow ground-based systems to do better than Hubble in the visible portion of the spectrum. For IR and UV stuff that never makes it thru the atmosphere, a space-based telescope is the only option.
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I'm no expert on the fear and politics surrounding HST, but I am an expert on the physics/astronomy front (IAAAP). That said, I am profoundly disturbed by NASA's decision to cancel future missions to extend the lifetime of the Hubble Space Telescope (HST).
Hubble is still profoundly useful, and even its proposed successor, the James Webb Space Telescope, cannot probe the same regions as HST. The reason has to do with the filters hooked up to it. James Webb is designed to view the highest redshift objects, so its filters are very red. The "bluest" light it can observe is about 600 nm, which appears yellowish-orange to our eyes, up to about 2000 nm, far into the infrared. HST can observe wavelengths between ~200 nm (ultraviolet) and ~850 nm (near infrared). I don't know why people keep spouting off that the James Webb is a superior replacement to HST, because it probes an entirely different type of light.
It's also worth noting that all of these extra-solar planets are gas giants, comparable to Jupiter-sized objects. The reason people are interested as far as life goes is not that they expect to find life on these planets, but that these planets may be indicators of other, Earth-type planets, in the same solar system.
No, JWST won't be "a lot better" than Hubble. It will be a lot better at the one kind of observing that it was designed for. However, HST was really good for many many different kinds of observing. This mission diversity is a large part of what makes HST so great. Not to mention the upgradability of HST (JWST will be unserviceable).
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What's really too bad is that most of your arguments are completely incorrect. First off, Hubble is a technological marvel -- it's current "best" detector, the ACS, is one of the most sophisticated instruments in the world. It is state-of-the-art. And the primary mirror is still outstanding (perfectly ground to the wrong, but _known_ shape).
Second, the new JWST will only work in the near infra-red. That is fantastic for cosmology, star formation and certain other sciences, but will not help with the optical and near-UV science that HST can provide.
And finally, while adaptive optics at most new ground based telescopes are doing great things, there are still _severe_ limitations to their use: only small fields of view are available and bright stars need to be nearby in the sky (this greatly limits the fraction of the sky that can be viewed by these systems). Note: yes, sodium laser-based AO systems can fix some of these problems, but the lasers are currently highly problematic and the systems have very low observing efficiency (i.e. useful scientific data per unit of telescope time).
So bottom line is that HST will be sorely missed by astronomers/astrophysicists. And yes, as a professional astronomer, I will be one of those missing it (even though most of my work is in the radio).
A moon-based scope has many advantages and disadvantages which should be considered.
/. assumption that anyone working in any field is an idiot? (Every /. story about any new device or invention leads with the usual "I wonder what they're going to do about X," where X is the blindingly obvious thing that any simian would have thought of first - yes, they've thought about it and actually done a calculation!).
They have considered it, thanks. Also scopes on the Antartic high ice cap, and earth-trailing, and at 5 AU, and at L2.
Why is there always an assumption that the folks at NASA are idiots? Or is that just the usual
It's incredibly expensive to softland devices on the moon, compared to orbiting them in space. There's no solar power for two weeks at a time, so you'd have to use nuclear, which limits the amount of power you can get (and nuclear power generators are heavy, so you can't just launch more). Assuming it's a visible wavelength telescope (IR just seems impossible with the temp variations), when you're in the shade, you have to keep things warmed up to room temp, and when you're in the sun, you have to shield them from the sun without blocking your aperture. Being on the moon severely limits pointing capabilities - you have to point where ever the moon is pointing (L2 satellites have to point anti-sun but that's less restrictive). In fact, when the sun is shining down your aperture, can you observe at all? There's no soft lander infrastructure in place (you can't call up Boeing and order a Delta IV with the moon soft landing option), so you'd have to develop that also. It would include landing a multi-ton very precise, irreplaceable mirror and deploying in a gravity field. Just seems like a design, cost, and risk nightmare. All this is robotic of course, unless you also want to pay for the infrastructure to put humans up there. Which would cost about the same as 5 or 10 Hubble equivalents. That would make the telescope the flea on the elephant's back and the first thing to be cut when the inevitable overruns happened.
Now where are the advantages? Or did you just say that because you think there are some but you really haven't thought about what they are, but hey, Hubble on the moon! That sounds cool! Right up there with "move the Hubble to the ISS" in terms of bad choices.
For those who follow this field, I'll remind you of the OGLE project, which has been doing the same thing from the ground. They found 60 likely planetary candidates (out of a similar number of stars monitored), but only two of those actually look like they could be planets. All the rest are either grazing-incidence binaries or blended binaries. The higher resolution of Hubble may help the blend problem to an extent, but I highly doubt the number of actual planets is anywhere near 100.
They also have little chance of confirming whether these are actually planets, as you need to do extremely high-resolution spectroscopy in order to confirm its existence via the radial velocity method. Even Keck can only do that for stars down to ~16th magnitude, and according to the observing proposal, this survey is going down to 23rd. They might be able to get precise-enough light curves to reject false positives based on color-curve changes, but I'd like to see it before I believe it.
Microsoft delenda est!
In case anyone's interested and prefers a little more science in their science reporting, here's the original proposal (it's a text file):
. pro
http://www.stsci.edu/observing/phase2-public/9750
A big aspect of this proposal *not* mentioned in the BBC article is the importance of metallicity on star formation - in other words, what star environments (old vs. young) form more planets.