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Did Ancient Supernovas Change Earth’s Climate?

Visible, infrared, and X-ray image of Kepler’s supernova remnant located about 13,000 light-years away. The bubble of ionized gas is about 30 light-years across. Credit: NASA, ESA, R. Sankrit and W. Blair (Johns Hopkins University).

Supernovas are some of the most powerful and energetic events in the entire Universe. When a dying star explodes you wouldn’t want to be anywhere nearby—fresh elements are nice and all, but the energy and radiation from a supernova would roast any planets within tens if not hundreds of light-years in all directions. Luckily for us we’re not in an unsafe range of any supernovas in the foreseeable future, but there was a time not very long ago (in geological terms) that these stellar explosions occurred nearby (in astronomical terms) and in 2016 scientists found the “smoking gun” evidence at the bottom of the ocean.

What’s more, the arrival of the iron-rich fallout from those stellar explosions seems to coincide with ancient global temperature changes*, the most recent dated near the start of the last major ice age which brought lower sea levels, widespread glaciation…and eventually the rise of the first modern humans.

Read more at Universe Today here: Nearby Supernovas Showered Earth With Iron

*Note: the changes in climate referred to here are not the same as the climate change we are witnessing today. Not only are we now seeing rapid warming of land and sea temperatures globally, but today’s forcings are the result of increasing greenhouse gases like carbon dioxide in the atmosphere—not radioactive iron from exploding stars.

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“Alien Megastructure” May Actually Be Scraps of an Ingested Planet

Artist’s impression of the star KIC 8462852, surrounded by randomly transiting objects. Credit: NASA/JPL

For the past couple of years the astronomy world has been abuzz with news of the strange and randomly-occurring dimming of the star KIC 8462852—aka Tabby’s Star—located 1,276 light-years away in the constellation Cygnus and recently observed by NASA’s Kepler spacecraft. Hypotheses about the cause range from conservative (a transiting cloud of comets) to quite speculative (an “alien megastructure” constructed around the star) but to date nothing seems to perfectly fit the observations. Now, researchers from Columbia University and UC Berkeley are proposing a new idea: the dimming of Tabby’s Star is being caused by debris left over from a planet that was consumed by the star thousands of years ago, the orbiting scraps from a case of stellar infanticide.

Read more in a Universe Today article by Matt Williams: Finally, An Explanation for the Alien Megastructure?

Breaking News: Kepler Team Spots First Earth-Sized Exoplanets

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The video above sums up the big astro-news of the day: NASA’s Kepler mission has confirmed the existence of not one but TWO Earth-sized planets orbiting a Sun-like star 1,000 light-years away. This is a big deal!

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Kepler Finds a Real-Life Tatooine

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Kepler, NASA’s exoplanet hunter extraordinaire, has confirmed the existence of the first planet orbiting two suns, not unlike Luke’s homeworld Tatooine from the Star Wars films! Unlike Tatooine, however, the planet –named Kepler-16b – is a cold Saturn-sized gas giant unlikely to harbor life. Still, it showcases the variety of planetary systems to be discovered and is another step from science fiction to science fact! Read the rest of this entry

Kepler’s Discovery: New Worlds for the Finding

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Today NASA held a press conference at 1pm EST to present the discovery of over 1,200 exoplanet candidates by the Kepler telescope, an orbiting space observatory that’s been watching a section of the sky near the constellation Cygnus for the past year and a half. (The spacecraft launched on March 6, 2009.) So far it has identified 1,253 planet candidates, 68 of which are Earth-sized – 54 of those within the habitable zone of their host stars. The most recent of these exoplanet systems is around a star labeled Kepler-11 2,000 light-years away, around which six planets have been identified – some close to the size of Earth, but not within its habitable zone. Still, a six-planet system is very exciting! For a good recap of the discovery watch the video above, it sums up the information delivered during today’s hour-long conference very nicely.

Needless to say this is a very exciting time for astronomy! Twelve years ago we didn’t even have confirmation of any planets outside our solar system. Before 2009 we only knew of a dozen or so. Now we have over 1,200…with more discovered every day. And this from searching a space only 1/400th of the area of the visible sky! Still, to quote Kepler principal investigator Bill Borucki, in order to find out if any of these planets may harbor life we will need “patience…and lots of money.” Let’s hope we can keep people excited about this, for science and for what it may mean about our place in the universe.

To watch the full press conference click here.

Video: NASA Ames Research Center

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