About Phil

Bio

I am an astronomer, author, public speaker, blogger, father, and inveterate punster. My passion is astronomy, and telling people about the wonders of nature. Science is the best thing we can do; studying the Universe is in many ways what makes us human. And increasingly - with our economy, medicine, and environment being as they are today - science is our best hope for the future.

Areas of Expertise

Astronomy and Space

An idea worth spreading

The Universe seems safe and static, but is in fact a dynamic place that affects us here on Earth all the time. It's only by studying it, understanding it, that our species can even hope to survive int he long run.

I'm passionate about

Astronomy, science, Doctor Who, space exploration, and far more topics than the allowed 81 characters I have left here.

People don't know I'm good at

Juggling, whistling, and being able to tell if pictures are hung on walls perfectly level.

Comments & conversations

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Phil Plait
Posted over 3 years ago
Phil Plait: How to defend Earth from asteroids
Actually, what you describe is just as bad as letting it hit intact. The same amount of energy is deposited on Earth, but now it's spread out and can do damage over a larger area. The damage from the meteor Crater impact was probably relatively local, while Tunguska - which was the same size explosion - did damage over a large area. The best thing to do is as I described: slam it to prevent it from hitting, then nudge it into a safe orbit.
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Phil Plait
Posted over 3 years ago
Phil Plait: How to defend Earth from asteroids
Well, only partially a joke. Jonas M, if we actually have the technology to move an asteroid and prevent it from impacting us, and then we do so, then *we've already saved ourselves from that threat*. So now we've got a working motor that can tug the asteroid where we want it. Why not put it in orbit around Earth and then mine it?
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Phil Plait
Posted over 3 years ago
Phil Plait: How to defend Earth from asteroids
An explosion is a very rapid release of energy. There are different kinds of explosions, but that's a good enough generic definition! An asteroid hitting the Earth has a LOT of energy, kinetic energy, which depends on its mass and its velocity. A big rock has a lot of mass, and it's traveling at 20 - 50 km/sec. That's fast! When it hits the Earth (or breaks up in our atmosphere) it gives up all that energy very rapidly in the form of heat. That's what causes the explosion!
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Phil Plait
Posted over 3 years ago
Question about the Yucatan crater
Hi Rik- It may be hard to see unless you make the talk full screen, but I displayed a little scale bar under the crater during the talk. It had two bars, one 50 miles long and the other 100km long, to show how big the Chixulub crater is.
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Phil Plait
Posted over 3 years ago
Should you be worried about an asteroid impact? Live Conversation with Phil Plait - Join now!
Actually, yes. If the asteroid spins, the heating of the Sun can act like a very low thrust rocket, called the YORP effect (you can look this up). That's very slow, acting over years,so it's something to keep track of but is not a major problem. Dark asteroids are a problem; ones that are so black they are difficult to detect. However, they still glow in the infrared, so we need telescopes that detect IR light (like WISE did) to find those. it's makes things more difficult, but we do have the means to find them!