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Kepler Discovers Solar System's Ancient 'Twin'

Posted by Soulskill on from the not-quite-sol-o dept.

astroengine writes: Astronomers have found a star system that bears a striking resemblance to our inner solar system. It's a sun-like star that plays host to a system of five small exoplanets — from the size of Mercury to the size of Venus. But there's something very alien about this compact 'solar system'; it formed when the universe was only 20 percent the age it is now, making it the most ancient star system playing host to terrestrial sized worlds discovered to date.

15 of 67 comments (clear)

  1. Um... by sootman · · Score: 4, Funny

    The only problem with naming satellites after early astronomers is that when I read the headline, there is a moment where I think "wait -- isn't he dead?"

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    1. Re:Um... by Penguinisto · · Score: 4, Funny

      ...could be worse; the kids could be asking "Who's this Hubble guy and where did he get that badass camera?"

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    2. Re:Um... by Tablizer · · Score: 2

      The next probe will be Zombie 2.

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  2. How are they rocky? by cusco · · Score: 3, Insightful

    I thought that it took multiple generations of supernovas to produce enough heavy elements to accumulate into a rocky planet.

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    1. Re:How are they rocky? by Penguinisto · · Score: 2

      I suspect it would depend on the star in question. A monster (e.g. Betelgeuse) likely has a gravity well strong enough to make 'em in larger quantities than our star does.

      Also, neutron stars and other near-black-hole masses could likely crank out heavy elements in shorter order.

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    2. Re:How are they rocky? by doug · · Score: 4, Insightful

      In the early universe, things were closer together (less time for expansion), and there were more large, hot stars. A stellar generation would have been faster than it is now. That said, it does sound a bit zippy.

    3. Re:How are they rocky? by Solandri · · Score: 4, Informative

      Depends on the composition of your "rocky" planet. Fusion reagents are energy-positive up to iron. So basically, elements heavier than iron requires multiple supernovae to generate a substantial quantity. Elements lighter than iron can be released in just 1-2 supernovae.

      The elements which make up most of the "rock" on our rocky planet are oxygen, silicon, calcium, iron, potassium, aluminum, and sodium. Of these, oxygen, silicon, and iron are a regular product of stellar fusion, and can be distributed from a single supernova.

    4. Re:How are they rocky? by reverseengineer · · Score: 2

      What's interesting about this star though, is that according to the paper, Kepler-444 is not some primordial supergiant, but a K dwarf (orange, of the same type as Alpha Centauri) with a smaller companion red dwarf (or possibly two companion red dwarf stars which are closely bound to each other).

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    5. Re:How are they rocky? by DM9290 · · Score: 2

      I suspect it would depend on the star in question. A monster (e.g. Betelgeuse) likely has a gravity well strong enough to make 'em in larger quantities than our star does.

      Also, neutron stars and other near-black-hole masses could likely crank out heavy elements in shorter order.

      matter inside a neutron star is effectively stuck forever. neutron stars are not a source of matter because they are essentially an end state of matter.

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  3. Last Season of Star Trek by painandgreed · · Score: 3, Funny

    Cue the Star Trek music as the Enterprise begins to circle yet another duplicate of the planet Earth. Spock turns to the Captain and says "It seems an exact duplicate of the Sol system, but formed billions of years earlier. Before even the creation of your solar system Captain. Most interesting."

  4. Crazy! by nightfire-unique · · Score: 3, Funny

    I thought he died years ago!

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  5. Brightness by Dan+East · · Score: 2

    They calculated that there are 5 planets orbiting the star by the way the intensity of the star dips very, very slightly in a pattern. Are we sure there are no other mechanisms that can cause the star's intensity to vary in a pattern? We only know about our own star's sunspots, and the longer term cycle (11 years) in which the sunspots change the intensity at which it emits. How do we know that a smaller, much older star doesn't have a sunspot type cycle that is shorter or more complex, and that is what is causing this star's intensity to change?

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    1. Re:Brightness by slew · · Score: 2

      They calculated that there are 5 planets orbiting the star by the way the intensity of the star dips very, very slightly in a pattern. Are we sure there are no other mechanisms that can cause the star's intensity to vary in a pattern? We only know about our own star's sunspots, and the longer term cycle (11 years) in which the sunspots change the intensity at which it emits. How do we know that a smaller, much older star doesn't have a sunspot type cycle that is shorter or more complex, and that is what is causing this star's intensity to change?

      Please refer to the Kepler FAQ

      Planetary transits have durations of a few hours to less than a day. The measured solar variability on this time scale is 1 part 100,000 (10 ppm) as compared to an Earth-size transit of 1 part in 12,000 (80 ppm). Even then, most of the variability is in the UV, which is excluded from the measurements by the Kepler Mission.

      Also concerning stellar variablity...

      Even for the Sun - a star of low rotation rate and relatively evenly distributed active regions (in longitude) - variability is concentrated at time scales comparable to the rotational period. Fortunately, the time scales of interest to planet detection are considerably shorter.

      One would hope that we can have enough faith in our friends at Nasa that they would do their homework (rather than just surf a few sites on the internet before launching a 1/2 billion dollar mission)...

  6. This is cool but scary because of Great Filter. by JoshuaZ · · Score: 2

    While this is really neat, it is yet more of the accumulating evidence that there are no substantial barriers to intelligent life arising or even arising in the early universe. This suggests that something is wiping out civilizations, possibly something the civilizations themselves all do. This problem is known as the Great Filter http://en.wikipedia.org/wiki/Great_Filter (Strictly speaking the Filter is whatever makes massive, interstellar, civilizations apparently rare, but it looks like most of the Filter really is at or beyond our rough tech level.) The Great Filter could be nuclear war, or epidemics, or biological warfare, or bad nanotech, or possibly something we haven't even thought of that comes completely out of left field. But the evidence for it is growing. This is scary.

  7. Re:How about 2.7 billion years old by geantvert · · Score: 2

    Hummm... I think you mean 2800BC