Earth is no Longer ‘One of a Kind’

For this special little planet, today has been a very big day.

Although we’ve speculated that planets the size of Earth must exist elsewhere in the cosmos, it wasn’t until one of the co-investigators working with the Kepler Space Telescope said he had statistical evidence that worlds of the approximate size of Earth appear to dominate our Milky Way.

We now know Earth isn’t unique.

Alas, this historic news didn’t come without controversy. It was unofficially broken at a TED conference in Oxford earlier this month and only after a recording of a presentation given by Dimitar Sasselov was posted online did the news get out. What’s more, the announcement only became clear when Sasselov referred to a presentation slide depicting a bar chart with the different sizes of exoplanets discovered by Kepler:

A slide from Dimitar Sasselov's TED presentation.

This slide shows the number of exoplanets discovered up until this month, binned by size. We have Jupiter-like exoplanets, Saturn-like exoplanets and Neptune-like exoplanets, all compared with Earth’s radius.

The heart-stopping moment comes when looking at the bar that represents Earth-like exoplanets (i.e. worlds with a radius of below 2 Earth radii, or “<2 Re"). According to Sasselov, Kepler has detected a lot of Earth-like worlds, so many in fact that they dominate the picture. From what we have here, it would appear that around 140 exoplanets are considered to be like Earth.

“The statistical result is loud and clear,” said Sasselov. “And the statistical result is that planets like our own Earth are out there. Our Milky Way galaxy is rich in these kinds of planets.”

But why the controversy? Isn’t this good news?

It would appear that the Kepler co-investigator chose not to wait until the official press release from NASA. He publicized these groundbreaking results in the U.K. at an event where you had to buy tickets to attend. This isn’t usually the stage you’d expect this kind of discovery to be announced — a move that will undoubtedly upset many.

“What is really annoying is that the Kepler folks were complaining about releasing information since they wanted more time to analyze it before making any announcements,” Keith Cowing, of NASAWatch.com, wrote in a SpaceRef article today. “And then the project’s Co-I goes off and spills the beans before an exclusive audience – offshore. We only find out about it when the video gets quietly posted weeks later.”

This sentiment is understandable. Only last month there was some frustration vented at the Kepler team for holding back data on 400 exoplanet candidates. While this might be standard practice — the discovering team should be allowed some time to publish work on any discoveries they have uncovered — telling the world’s scientists they will have to wait until February 2011 before they can get their hands on this invaluable data was a bridge too far.

In light of this, for a Kepler scientist to then jump the gun and disclose a groundbreaking discovery at an international conference without the backing of an official NASA release seems a little hypocritical.

But there is another argument to put out there: Why should anyone sit on such a profound discovery? Perhaps NASA and the Kepler team should have issued an earlier press release announcing to the world that 140 candidate Earth-like worlds have been detected and that further work will need to be done to confirm.

Ultimately, this controversy is just background noise when compared to what we have learned today. Official confirmation or not, Dimitar Sasselov’s message is clear. Although these detections need to be confirmed (hence why these worlds are referred to as “candidates”), it would appear there is an overwhelming preponderance of exoplanets measuring 2 Earth radii or less.

For me, that fact alone is astonishing — the first scientific evidence that worlds of Earth dimensions are not rare.

Earth is no longer unique.

For more, read my Discovery News article, “Kepler Scientist: ‘Galaxy is Rich in Earth-Like Planets‘”

Has Kepler Discovered a New Class of Celestial Object?

The strange objects orbiting the two stars could be mangled white dwarfs... but the jury is still out (NASA)

The first results from NASA’s Kepler exoplanet hunter are in and a perplexing early result has been announced. Yes, the space telescope is working fine, and no, it hasn’t spotted an alien homeworld (yet), but the Kepler team have uncovered something pretty cool.

Kepler may have discovered a new class of celestial object (possibly).

But before we start scratching our heads in confusion or popping the champagne corks in celebration, let’s try to work out what Kepler has observed.

Kepler is currently monitoring 100,000 stars in an effort to seek out extra-solar planets (or “exoplanets”) orbiting these stars. Although Kepler was only launched in March 2009 and early doubts about the observatory’s capabilities caused some low-level concern, Kepler appears to be functioning well and mission controllers are already reporting early results.

Five new exoplanet discoveries by Kepler were announced at the American Astronomical Society (AAS) meeting in Washington D.C. on January 4th, and all seem to have very strange characteristics. Fortunately Discovery News blogger Ray Villard was on the scene at the AAS to hear what the Kepler team had to announce:

In sifting through the Kepler data taken so far, postdoctoral student Jason Rowe found a very curious light signature. When an object passed behind its central star, the light from the system dropped significantly. This means the object — called KOI 74b — must be glowing fiercely with its own light that was blocked out when the object was eclipsed.

Hold up, the light dimmed when the exoplanet passed behind its parent star? Something’s not right here. Kepler detects exoplanets when the worlds pass in front of their parent stars, thereby dimming the starlight, not vice versa!

Actually, this is exactly what’s happened. The “exoplanets” orbiting two otherwise ordinary stars appear to be brighter — and hotter — than their host stars. It’s as if the roles of the stars and the exoplanets have been reversed; the stars are dimming the exoplanetary light as the exoplanet passes behind the star.

Needless to say, there is currently no stellar model that predicts this kind of behavior from extra-solar planetary systems.

This means the object — called KOI 74b — must be glowing fiercely with its own light that was blocked out when the object was eclipsed […] It is seething at 70,000 degrees Fahrenheit while the parent star is 17,000 degrees Fahrenheit. The strange object can’t be a star because the transit data show that it is no bigger than Jupiter.Ray Villard, Discovery News.

One theory is that KOI 74b (and the other strange object, KOI 81b) could be a white dwarf star that migrated close to its stellar partner. Through binary interactions, the white dwarf was stripped of some of its mass, causing it to puff up and appear like a gas giant exoplanet. That would certainly go to some way of explaining why these two “exoplanets” are so hot.

Of course, the other option is that Kepler has made a groundbreaking discovery and identified a whole new class of celestial object… but I suspect there are other, more mundane reasons for these observations.

I suppose we’ll just have to wait and see until followup observations are made…

Source: Discovery News

New Addition to the Exoplanetary Menu: The WASP-12b Sizzler

The hotspot: A very, very hot Jupiter has been discovered (ESA/C Carreau)
The hotspot: A very, very hot Jupiter has been discovered (ESA/C Carreau)

So how hot is the hottest known planet? Usually the temperature of a planet orbiting another star is of little concern to us. At the end of the day, are we really looking for an interstellar getaway? The chance that we’ll be colonizing any extra-solar planets in the near future is pretty low, but that won’t stop us from peering up the the heavens studying “Hot Jupiters” orbiting stars hundreds of light years away. However, astronomers have just discovered a planet I doubt we’ll ever want to visit. Enter WASP-12b, the hottest, and fastest gas giant ever observed…
Continue reading “New Addition to the Exoplanetary Menu: The WASP-12b Sizzler”