Oct 22, 2015 05:54 PM
Kepler Observes White Dwarf Star Disintegrating Its Planet(s)
EXCERPT: One of the wonderful things of living in a galaxy populated by hundreds of billions of stars is that it provides us with the chance to understand the latter’s entire evolutionary path from birth to death, just by observing the galaxy’s many different stellar populations. This fact has just become even clearer by the Kepler space telescope’s newest and somewhat coincidental discovery of a white dwarf star caught in the act of devouring the left-over remains of its planetary system. Besides being fascinating in their own right, these first-ever observations of planetary cannibalism around a white dwarf also provide a glimpse of our own Solar System’s future five billion years from now, when the Sun will have been reduced to an inauspicious stellar remnant after destroying most of the planets, including Earth....
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Controversy: Objects Orbiting New Star Likely Cometary Fragments, Not Aliens
EXCERPT: [...] The discovery was certainly unusual: The star was apparently surrounded by a mass of objects, in a relatively tight formation, blocking out a significant amount of the star’s light as they orbited. Could it be a debris disk, as seen around many other stars? That would be possible, except for one problem: those are found around young stars which are still forming [...] But KIC 8462852 is not a young star, so any debris disk should be long gone by now, other than perhaps smaller asteroids and comets like in our own Solar System. Also, debris disks give off extra infrared light, but none was detected in this case. So what about planets? That would seem to be an obvious possibility. There are problems with that scenario, too. [...]
[...] Things started to get more interesting when Boyajian acknowledged that other scenarios were still possible. What scenarios? Well, aliens for one. The finding caught the attention of Jason Wright, an astronomer at Penn State University [...] A good overview of Wright’s position on the matter is available here on his blog. There is also a new paper in the Astrophysical Journal just published by Wright and other colleagues, ‘The Gˆ Search for Extraterrestrial Civilizations With Large Energy Supplies. IV. the Signatures and Information Content of Transiting Megastructures,’ which discusses the KIC 8462852 discovery (section 4) as well as other possible candidates....
[...] The new paper by Kepler scientists attempts to explain the findings, focusing on natural explanations. From the abstract:
“Over the duration of the Kepler mission, KIC 8462852 was observed to undergo irregularly shaped, aperiodic dips in flux down to below the 20% level. The dipping activity can last for between 5 and 80 days. We characterize the object with high-resolution spectroscopy, spectral energy distribution fitting, and Fourier analyses of the Kepler light curve. We determine that KIC 8462852 is a main-sequence F3 V/IV star, with a rotation period ∼ 0.88 d, that exhibits no significant IR excess. In this paper, we describe various scenarios to explain the mysterious events in the Kepler light curve, most of which have problems explaining the data in hand. By considering the observational constraints on dust clumps orbiting a normal main-sequence star, we conclude that the scenario most consistent with the data in hand is the passage of a family of exocomet fragments, all of which are associated with a single previous breakup event. We discuss the necessity of future observations to help interpret the system.”
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Life on Earth May Have Started Almost Instantaneously
EXCERPT: "We need to think differently about the early Earth," says Elizabeth Bell of UCLA. The early Earth certainly wasn't a hellish, dry, boiling planet. A UCLA team of geochemists see absolutely no evidence for that. The planet was probably much more like it is today than previously thought the team concluded. The UCLA scientists have found evidence that life likely existed on Earth at least 4.1 billion years ago -- 300 million years earlier than previous research suggested. The discovery indicates that life may have begun shortly after the planet formed 4.54 billion years ago....
EXCERPT: One of the wonderful things of living in a galaxy populated by hundreds of billions of stars is that it provides us with the chance to understand the latter’s entire evolutionary path from birth to death, just by observing the galaxy’s many different stellar populations. This fact has just become even clearer by the Kepler space telescope’s newest and somewhat coincidental discovery of a white dwarf star caught in the act of devouring the left-over remains of its planetary system. Besides being fascinating in their own right, these first-ever observations of planetary cannibalism around a white dwarf also provide a glimpse of our own Solar System’s future five billion years from now, when the Sun will have been reduced to an inauspicious stellar remnant after destroying most of the planets, including Earth....
- - - - - - -
Controversy: Objects Orbiting New Star Likely Cometary Fragments, Not Aliens
EXCERPT: [...] The discovery was certainly unusual: The star was apparently surrounded by a mass of objects, in a relatively tight formation, blocking out a significant amount of the star’s light as they orbited. Could it be a debris disk, as seen around many other stars? That would be possible, except for one problem: those are found around young stars which are still forming [...] But KIC 8462852 is not a young star, so any debris disk should be long gone by now, other than perhaps smaller asteroids and comets like in our own Solar System. Also, debris disks give off extra infrared light, but none was detected in this case. So what about planets? That would seem to be an obvious possibility. There are problems with that scenario, too. [...]
[...] Things started to get more interesting when Boyajian acknowledged that other scenarios were still possible. What scenarios? Well, aliens for one. The finding caught the attention of Jason Wright, an astronomer at Penn State University [...] A good overview of Wright’s position on the matter is available here on his blog. There is also a new paper in the Astrophysical Journal just published by Wright and other colleagues, ‘The Gˆ Search for Extraterrestrial Civilizations With Large Energy Supplies. IV. the Signatures and Information Content of Transiting Megastructures,’ which discusses the KIC 8462852 discovery (section 4) as well as other possible candidates....
[...] The new paper by Kepler scientists attempts to explain the findings, focusing on natural explanations. From the abstract:
“Over the duration of the Kepler mission, KIC 8462852 was observed to undergo irregularly shaped, aperiodic dips in flux down to below the 20% level. The dipping activity can last for between 5 and 80 days. We characterize the object with high-resolution spectroscopy, spectral energy distribution fitting, and Fourier analyses of the Kepler light curve. We determine that KIC 8462852 is a main-sequence F3 V/IV star, with a rotation period ∼ 0.88 d, that exhibits no significant IR excess. In this paper, we describe various scenarios to explain the mysterious events in the Kepler light curve, most of which have problems explaining the data in hand. By considering the observational constraints on dust clumps orbiting a normal main-sequence star, we conclude that the scenario most consistent with the data in hand is the passage of a family of exocomet fragments, all of which are associated with a single previous breakup event. We discuss the necessity of future observations to help interpret the system.”
- - - - - - -
Life on Earth May Have Started Almost Instantaneously
EXCERPT: "We need to think differently about the early Earth," says Elizabeth Bell of UCLA. The early Earth certainly wasn't a hellish, dry, boiling planet. A UCLA team of geochemists see absolutely no evidence for that. The planet was probably much more like it is today than previously thought the team concluded. The UCLA scientists have found evidence that life likely existed on Earth at least 4.1 billion years ago -- 300 million years earlier than previous research suggested. The discovery indicates that life may have begun shortly after the planet formed 4.54 billion years ago....