extinct comet

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Are Mass Extinctions Periodic, And Are We Due For One?

“If we start looking at the craters we find on Earth and the geological composition of the sedimentary rock, however, the idea falls apart completely. Of all the impacts that occur on Earth, less than one quarter of them come from objects originating from the Oort cloud. Even worse, of the boundaries between geological timescales (Triassic/Jurassic, Jurassic/Cretaceous, or the Cretaceous/Paleogene boundary), and the geological records that correspond to extinction events, only the event from 65 million years ago shows the characteristic ash-and-dust layer that we associate with a major impact.”

65 million years ago, a catastrophic impact from outer space caused the last great mass extinction on Earth, destroying 30% of the species that lived on our world at the time. These mass extinction events happened many times in Earth’s past, and the Solar System also passes through denser stellar regions of space periodically, as determined by the orbit of the Sun and stars in the Milky Way. It’s a combination of facts that might make you wonder whether the extinction events are also periodic, and if so, whether periodic impacts are predictable. If so, then shouldn’t we be aware of whether we’re living in a time of increased risk, and prepare ourselves for that possibility accordingly? After all, the dinosaurs didn’t have a space program or the capability of deflecting a dangerous object like the one that wiped them out.

But before we go that route, we should take a good look at what the data shows. Are mass extinctions periodic? Are we due? Let’s find out!

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E.L.E. - Extinction Level Event - frame by frame

Although there are 10–14 million species of life currently on the Earth, it is estimated that more than 99 percent of all species that ever lived on the planet are extinct.


Jan ( donleyjan ), in her Magic City 3 drawing, pointed out how Fill can make a great starry night sky, so I thought it would also be great for creating a space background for a space drawing (frame 1).

I also tried out the new Smart Pen to create planet Earth, but I actually ended up refining the circle, because it didn’t have a smooth outline.

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No, Earth Is Not Overdue For A Massive Asteroid Strike

“The odds of a massive asteroid strike are lower than they’ve ever been at any point in Earth’s history. Small asteroids will still hit us and we should still invest in the study and exploration of our Solar System and beyond, but we shouldn’t be afraid. The “quietness” of the past few millennia doesn’t mean we’re overdue for a city-killer asteroid; if anything, it means we’re living in a period of relatively low risk. Don’t let the catastrophic consequences in the game of “what if” blind you to the realities that of all the natural and human-caused disasters facing Earth, asteroids aren’t the one that should be topping our priority lists.”

Between recent statements from NASA, the American Geophysical Union and Los Alamos National Laboratory, you might think that humanity is overdue for a catastrophic impact from outer space. Indeed, it’s been a long time since we’ve had one that was very destructive, and other than the 1908 Tunguska blast, we haven’t had one that even registered on the Torino Scale in millennia. But the lack of recent events doesn’t mean that our odds of having one are increased in the near future. Quite to the contrary: they are likely a symptom of the fact that we’re living in an epoch where the odds of an impact are among the lowest they’ve ever been in human history. While the probability is still non-zero in any given year, and while space exploration and studying our Universe is of great importance, it isn’t to save our world from a killer rock from outer space.

It’s possible to be aware of an appreciate space without being terrified of it. Find out what the science actually says!

December’s Super-Moon 2016

Two bright celestial scenes are going to play out in the heavens on Tuesday night and Wednesday morning: a supermoon and a meteor shower.

While the supermoon of November was the subject of plenty of attention, the evening of December 14 will also host a supermoon, which is a phenomenon that occurs when the moon (which has an elliptical orbit) is closest to our planet at the same time it appears to be full from our vantage point here on Earth. The combination of the two factors makes it brighter— as much as 30 percent, NASA says.

An extra bright full moon makes for a powerful sight in the sky, but it’s going to outshine another phenomenon: the annual Geminid meteor shower, when the Earth passes through material from an “extinct comet” dubbed 3200 Phaethon, according to NASA. The meteors streak across the sky as they burn up, making for stunning shooting stars.