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Back in the eighties people laughed at scientists who talked about the threat from asteroids. Then we got better tools, and started tracking them. Now we are finding more every night.
Not only are there 27,000 near Earth asteroids that we know of, in the rest of the solar system we have found a few more, like 750,000. All this since the late 1990s.
Some computer somewhere is tracking all those orbits and arcs into the future. How often do these rocks run into each other and generate surprises?
Just how many threatening asteroids are there? It’s complicated.
By Meghan Bartels
“If you talk to the scientists who were studying this in the ’80s, there’s a phrase they often refer to called the giggle factor,” Carrie Nugent, a planetary scientist at Olin College in Massachusetts, told Space.com. “They’re basically saying that they couldn’t talk about this scientific topic without people kind of laughing at them.”
It looks like we’ve probably found all the big one-kilometer-wide asteroids that might pose a problem. And the little rocks will just burn up on entry. So it’s the middle sized ones (140m – 1000m) that we don’t know […]
Feel the guilt in the Gaia religion: New map shows alarming growth of the human footprint
“Humans are the most voracious consumers planet Earth has ever seen. With our land-use, hunting and other exploitative activities, we are now directly impacting three-quarters of the Earth’s land surface,” said Professor Laurance.
And three-quarters of 30% of the world is a fifth of the world. But algae will be feeling pretty cheezed right now. They wrecked up the whole atmosphere — but get no credit. Algae define the term “voracious consumer”. The pristine state of the atmosphere was transformed forever, plus the schmucks made oil.
But nothing changes the planet quite like a 10-20km wide rock dropping in and wiping out 90% of all species on Earth. That’s a “footprint”.
Note the magical 97% appears again — a sacred number of “certainty”:
A James Cook University scientist says a new map of the ecological footprint of humankind shows 97 per cent of the most species-rich places on Earth have been seriously altered.
9.3 out of 10 based on 52 ratings […]
Compare the tallies. Sixty-five million years ago an asteroid smacked-down and only 10% of mammal species survived. So far in the Anthropocene Catastrophe, one type of rat has been wiped off a 300m island.
Press Release Mammals almost wiped out with the dinosaurs
A study by researchers at the Milner Centre for Evolution at the University of Bath and published in the Journal of Evolutionary Biology, reviewed all mammal species known from the end of the Cretaceous period in North America. Their results showed that over 93 per cent became extinct across the Cretaceous-Paleogene (K-Pg) boundary, but that they also recovered far more quickly than previously thought.
Afterwards, mammalian life recovered with unexpected speed and diversity. Chalk one up to nature and evolution. Not so fragile?
8.8 out of 10 based on 51 ratings […]
50,000 years ago a bit of wayward rock about 50m across met Earth and left this 1200m wide crater in Arizona.
Ponder the momentum of 50m bit of rock that left a hole over a kilometer wide and 200m deep.
If one was coming. Would we know?
…(Click to enlarge) Photo not by JoNova
Thanks to NASA and The Earth Observatory
UPDATE: JoeV in comments adds an interesting link to Tracking space junk at Satview.org. An old satellite is coming in right now. It’s over Alaska (moving fast) at 153km high and falling quickly. Cosmos 1220, a Soviet era military surveillance satellite. Eddie adds a different link which suggests Cosmos is expected to crash into the Pacific in hours. Amazing what you can find out on the Internet.
9.2 out of 10 based on 51 ratings
The two asteroids were going in opposite directions, so were not related.
While everyone was expecting and watching Asteroid 2012DA14, which missed Earth by 26,000 km (17,000 miles), another asteroid blasted through the atmosphere in Russia, injuring more than 1,000 people (mostly by shards of glass caused by the sonic boom). One estimate makes it out to be a 10 tonner (seems a bit small), traveling at 30 kilometers a second. Another astronomer, Margaret Campbell-Brown, claims ultrasound stations show it was 15m wide and around 40 tonnes. Nature quotes the same researcher talking about 15m and 7,000 tonnes. You can see we have a good grip on what happened. [UPDATE: Now it’s 10,000 tons and 55 feet wide and stone. The largest object to hit in a century. WUWT. What about the ones that fell over the ocean wonders Jo? How would we know?]
It left a “contrail” and a flash that could be seen for 700km (see these videos –why are people filming while they drive?). It only “missed” by 30 – 50 kilometers and nobody knew it was coming. How little we know. One part of it broke off and smashed into a frozen lake, leaving a 6m […]
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JoNova A science presenter, writer, speaker & former TV host; author of The Skeptic's Handbook (over 200,000 copies distributed & available in 15 languages).
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