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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Space is full of rocks. We’ve found 27,000 near Earth Asteroids (so far)

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 […]

Landmark: First photo of a black hole (and Einstein was right)

A brief break in transmission now for the first photograph of a black hole, looking pretty much exactly as anyone would expect it to. The photons caught in this image traveled for hundreds of years at the speed of light. Lots of “hundreds” — burning through space for some 55 million years.

The numbers melt neurons: The supermassive black hole called M87 is 6.5 billion times bigger than our Sun. It’s bigger than the orbit of Neptune (which is circling 30 times further out from the Sun than we are). This star is 10 billion kilometers across.

Geoffrey Crew, a research scientist at Haystack Observatory commented that “With the M87 black hole being so massive, an orbiting planet would go around it within a week and be traveling at close to the speed of light.”

The black heart of Messier 87, or M87, a galaxy within the Virgo galaxy cluster, 55 million light years from Earth.

It takes a telescope roughly as big as The Earth to catch an image 20 micro-arcseconds across. Eight radio telescopes were combined across four continents and lined up on a few special days when they all had clear weather together. Each telescope took […]