Hello, this is Hank Green. Welcome back to SciShow News. It's record setting straight time again and you and I have got a lot to discuss: from the rain of spiders in Brazil that you may of heard about, to a new virus that's has got the internet all a-Twitter, to another asteroid that was recently found to have hit the Earth - and I'm not talking about the one in Siberia. Are you ready for some data?

(Intro)

Okay, you're on Facebook, I'm on Facebook, so I know you've seen it and you're probably still compulsively wiping the invisible crawlies out of your hair.

Last week, a video made the rounds showing what was purported to be a rain of spiders showering down on a neighborhood in Brazil. Thousands of arachnids in the air with people skeeving out in what I can only imagine is Portuguese for "Oh God, Oh God no". But as is so often the case, what the internet showed us may not be what is reality. There was not a rain of spiders, it turns out. But the real story behind the footage is pretty fascinating and only slightly less creepy than what the meme would have you believe.

The video was shot in Santo Antônio da Platina in South East Brazil and shows the sky overhead peppered with fat, brown spiders. But if you actually go past the OMG status update of that friend of a friend and actually watch the video, you'll see that they're not raining down on anyone. What you're looking at is a sheet web - a giant hammock made of spider silk designed for 8-legged communal living.

The spiders are the species Anelosimus eximius, I don't know exactly how to pronounce that, which are known to scientists as the most social of the so-called "Social Spiders" and boy, howdy, yeah. Colonies of A. eximius can contain as many as 20,000 spiders with several generations living together in webs, several meters across, that can last for years.

Unlike most other spiders, which seem to never find a bad time to eat one another, like during sex, right after being born or just because they're peckish, A. eximius have found success through co-operative living. Colonies are typically started by females and can quickly grow from a couple dozen to several thousand. Adults rear each others babies, share duties defending the colony from predators and spin their giant web together. And that helps each of the individuals save the precious energy that goes into making silk.

What's more scientists have found that their sheet webs actually capture fewer individual insects, but the ones that they do catch are much larger. Full grown colonies can catch bugs that are up to 20 times larger that what smaller webs can, which makes easier living for everyone.

Now if you go back and watch that video again, knowing that, doesn't it just make you feel all warm and fuzzy inside?

Speaking of faux-science in the news, you might have also heard of a new virus that's making the rounds, that has the media going "its SARS all over again". Even though, SARS turned out to be not that big of a deal.

The virus is so new that it hasn't even got a catchy acronym yet. If you've heard of it, you've probably heard it referred to as the Novel Coronavirus or NCoV-EMC. Very little is known about it, so perhaps it makes sense to feel a little wary, but since it was first discovered last April only 12 cases have been reported: 10 contracted in Saudi Arabia, Qatar and Jordan, probably from local animals and so far the infections have resulted in 5 deaths.

Though a study of the area's wildlife has yet to be released, virologists suspect that the vector that's spreading the virus is bats. But there's some good news, there's not much evidence that humans themselves are a good vector for the virus because nobody connected to any of the first 9 reported cases, either family members or healthcare workers, have fallen ill. The exception is the 10th case. A visitor to the Middle East carried the virus back to England, where he passed it to 2 family members: one of whom had a weakened immune system from having been sick before; and the other appears to only have a mild case of the infection. Moreover in a study released on Tuesday in the journal of the American Society for Microbiology, Swiss biologists say that the virus appears to be very comfortable in human tissues and is skilled at evading the human immune system. But it's so well adapted, they say, that it wouldn't be surprising if the virus has infected more people who just don't show severe symptoms.

So, what does NCoV have to do with SARS: the virus that infected 8000 people and killed 774 ten years ago? Well, aside from being respiratory infectors, both viruses are member of the family Coronaviridae which feature protrusions called 'Virions' around their fringes which makes them resemble crowns or coronas. So its related to SARS, yes, but for that matter so is HCoV-229E: the virus that causes the common cold. So being related to SARS really isn't anymore concern for widespread panic than that sick day you took last week, when you had a sore throat but mostly wanted to catch up with season 3 of Downton Abbey, before the finale.

But since I brought it up, there are some precautions you might want to take to avoid respiratory infections like NCov-EMC. Like SARS and the common cold, microbiologists think that Novel Coronavirus is spread through sneezes and coughs, so wash your hands, stop touching your face all the time and if at all possible, avoid other people's spit - I know it's hard but you can thank me later.

Finally, if you're like me you're probably still gawking in awe over last week's meteorite impact in Russia. As I sit here, 1200 people have been injured and millions of dollars in damage have been caused. All by a space rock, about 17 meters across that struck while the whole world's head was turned to watch the passing of another do-nothing asteroid - 2012DA14.

Well as if we needed another reminder that the universe is a big busy place and we can often get in its way, geologists say that they've discovered evidence of a truly huge asteroid impact that may be responsible for one of the biggest extinction events in Earth's history and it's sitting smack in the middle of Australia.

Geologists at Australian National University and the University of Queensland have been analyzing rock samples deep under central Australia and say that the formation they've discovered is the 3rd largest impact crater on Earth. It stretches some 300 km across and covers 33,000 square kilometers, just a few kilometers below the province of South Australia.

The geologists detected evidence of seismic activity and deformities in quartz crystals buried there that they say can only have been caused from an impact shock from a very large meteorite that struck the Earth from 280 to 360 million years ago.

What's more, geologist Andrew Glikson says that the newfound crater is the twin of another he and his team found last year, not far away in South Western Queensland. They suspect that the two impacts were created from the same object that split up upon entering the Earth's atmosphere. The larger chunk, probably as much as 20 kilometers wide, created the crater that they just reported last month and the timing of the impact coincides with the 'Late Devonian Extinction Event' which was really one piece of bad news after another for Earth for about 20 million years, ultimately wiping out about half of the world's genera. The mega impacts described by the Aussie geologists are probably part of that global calamity. Which makes last week's scrape with a space rock, despite all the harm it caused, seem like something to be thankful for. 

You can read all about it in the Journal of Tectonophysics linked below if you haven't got your issue in the mail yet.

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