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from the Super-Mega-Ultra dept.
ScienceDaily reports that Astronomers find a new type of planet: The "mega-Earth":
Astronomers announced on June 2nd that they have discovered a new type of planet a rocky world weighing 17 times as much as Earth. Theorists believed such a world couldn't form because anything so hefty would grab hydrogen gas as it grew and become a Jupiter-like gas giant. This planet, though, is all solids and much bigger than previously-discovered "super-Earths," making it a "mega-Earth."
The planet, Kepler-10c, orbits its host star every forty-five days at a quarter of the average distance between the Sun and Earth. It has a radius more than double that of Earth, but a higher density, making it the largest and most massive rocky planet discovered as of June 2014.
The story notes another aspect of Kepler-10c that complicates our understanding of planet formation:
The discovery that Kepler-10c is a mega-Earth also has profound implications for the history of the universe and the possibility of life. The Kepler-10 system is about 11 billion years old, which means it formed less than 3 billion years after the Big Bang.
The early universe contained only hydrogen and helium. Heavier elements needed to make rocky planets, like silicon and iron, had to be created in the first generations of stars. When those stars exploded, they scattered these crucial ingredients through space, which then could be incorporated into later generations of stars and planets.
This process should have taken billions of years. However, Kepler-10c shows that the universe was able to form such huge rocks even during the time when heavy elements were scarce.
So the question becomes how such a planet could have accumulated so much rocky material when so little was generally available at the time without also accumulating a large amount of gas and becoming a gas giant like Neptune and Jupiter.
See also: The Kepler-10 planetary system revisited by HARPS-N: A hot rocky world and a solid Neptune-mass planet [abstract] and full article (pdf)
(Score: 1, Redundant) by crutchy on Tuesday June 03 2014, @08:48AM
...goes with red mega planet, and yellow mega planet, to make the ultra mega mega planet. you have to have all three or it doesn't work, see"
(Score: 4, Interesting) by AnonTechie on Tuesday June 03 2014, @09:35AM
What qualifies this planet as Mega-Earth ?? It does not have liquid water, it is too hot, it orbits too close to it's star, the planet is much larger than earth ...
Albert Einstein - "Only two things are infinite, the universe and human stupidity, and I'm not sure about the former."
(Score: 5, Informative) by GreatAuntAnesthesia on Tuesday June 03 2014, @11:18AM
It's rocky, as opposed to gassy or icy. As far as most exo-planet hunters and/ or attendant journalists are concerned, that seems to be enough to describe a world as "Earth-like".
(Score: 2, Informative) by laserfusion on Tuesday June 03 2014, @03:02PM
Liquid water might exist on the surface. At 485 K surface temperature, it needs only a little higher atmospheric pressure than Earth to have liquid water. With 3x the surface gravity this is easily possible.
But it might not be habitable for humans without protection.
(Score: 2, Interesting) by GreatAuntAnesthesia on Tuesday June 03 2014, @12:02PM
(Score: 0) by Anonymous Coward on Tuesday June 03 2014, @08:43PM
It's just the Elcor Homeworld!
http://masseffect.wikia.com/wiki/Elcor [wikia.com]
(Score: 2) by M. Baranczak on Tuesday June 03 2014, @02:36PM
They're looking at a tiny dot on the screen, and making calculations based on tiny variations in the dot's position and brightness. They can't even see the planet directly. Whenever we see these articles, they report a single number for the planet's size, as if they can determine it exactly. Seems to me that there should be a pretty wide margin of error.
(Score: 2) by GreatAuntAnesthesia on Tuesday June 03 2014, @04:15PM
Your doctor can't see a virus directly, but when you get ill s/he can can give you a pretty accurate diagnosis of what's wrong with you. Same for pretty much anything happening between individual atoms or molecules - ie all of chemistry and biology.
When you're dealing with the then you generally have to use inference. I think it's fair to say that science has gotten pretty good at it, over the years. There will be a margin of error, but I'm pretty sure the astronomers of TFA will be very sure of their findings, and I'd be willing to trust the margin of error they have assigned to them. [youtube.com]
(Score: 2) by GreatAuntAnesthesia on Tuesday June 03 2014, @04:17PM
Gah! Ganked my link!
When dealing with the very small or very far away [youtube.com]...
(Score: 2, Informative) by resignator on Tuesday June 03 2014, @04:41PM
There is more than one way to look at a planet. Once a planet is detected by a method like radial velocity scientist take a closer look to determine the planet's composition, how close it orbits, size of the planet, etc. using a whole host of methods.
Oblig wiki link: http://en.wikipedia.org/wiki/Methods_of_detecting_exoplanets/ [wikipedia.org].
Here is another list of exoplanet search projects and what they are capable of:
http://en.wikipedia.org/wiki/List_of_exoplanet_search_projects/ [wikipedia.org]
Scientists typically dont make these things up. They can be wrong but rarely would one lie when the whole scientific community is going to take a second look anyhow. That whole peer review thing tends to keep the dishonest ones in check while simultaneously destroying their career.
(Score: 3) by M. Baranczak on Tuesday June 03 2014, @05:51PM
You have to remove the trailing slash:
http://en.wikipedia.org/wiki/Methods_of_detecting_exoplanets [wikipedia.org]
http://en.wikipedia.org/wiki/List_of_exoplanet_search_projects [wikipedia.org]
Yeah, I'm pretty sure that the scientists weren't just making shit up. I was just curious about the details: what the margin of uncertainty is, what factors affect it, were the measurements corroborated by different methods, etc. Your first link actually answered some of my questions, although it's information that's not specific to this planet.
(Score: 2, Interesting) by Yog-Yogguth on Tuesday June 03 2014, @03:41PM
Maybe it's hollow?
*runs away*
Bite harder Ouroboros, bite! tails.boum.org/ linux USB CD secure desktop IRC *crypt tor (not endorsements (XKeyScore))
(Score: 1) by ScriptCat on Tuesday June 03 2014, @08:46PM
Can the humans survive on a planet with 3g of gravity?