Tag: asteroids

"Armageddon" had bad science. Shocker, I know.

By Phil Plait | September 7, 2012 7:00 am

I do so love to make fun of the movie "Armageddon". I know, it’s such an easy target, but still.

I talk about the movie when I give public lectures about asteroid impacts, because a lot of people have seen it – so it’s a nice common point of contact – and because it really goes out of its way to get so much stuff wrong.

The premise of the movie is that a giant asteroid is going to hit the Earth and wipe out all life. I’ll skip a vast amount of silliness and get to the thing that really made me laugh out loud when I first saw the flick: to prevent the impact, astronauts plant a nuclear bomb below the surface and detonate it. This splits the asteroid in half, and (SPOILER ALERT!) the two pieces are flung apart at sufficient velocity that they pass our planet on either side, missing us, and the world is saved!


Well, not so much. I saw the movie when it came out in 1998, and after I got home from the theater – and after the Tylenol kicked in – I did a little math. We know how big the asteroid is, and what it’s made of – that gives us the mass (and therefore the mass of each half after it’s split). We also know how rapidly it’s approaching the Earth, and how far it was from the Earth when the bomb went off. That then can be used to figure out how fast the two halves separated (they had to separate by at least the Earth’s diameter to miss us).

An object in motion has energy, called kinetic energy. It depends on the mass of the object and its velocity – the more massive it is, or the faster it moves, the more kinetic energy it has. In the case of the Armageddon asteroid, the two halves got their kinetic energy from the bomb, so by calculating the kinetic energy of each piece you can find the explosive yield of the bomb.

I did that. The bomb would have exploded with roughly the same energy output as the Sun. In other words, it would have been a 100 billion megaton bomb. Yikes.

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CATEGORIZED UNDER: Astronomy, Geekery, Humor

The softly glowing zodiac: lesson learned

By Phil Plait | July 12, 2012 6:57 am

Every day I post a short, pithy astronomy or space fact on Twitter and Google+. I call them BAFacts, and I have them all archived here on the blog. I try to make them as accurate as possible within the limitation of 140 characters. But I wrote one recently that, as it turns out, I had to retract for being incorrect. And I’m happy about it! Here’s why.

I recently was going through old posts and saw one that mentioned zodiacal light, a very faint glow in the sky that can only be seen on very dark nights. It’s a band of light that follows the path of the planets across the sky, which is technically called the ecliptic. It passes through the constellations of the zodiac, hence its name*.

This picture of the zodiacal light is by friend of the BABlog Brad Goldpaint [click to embiggen, and note this is a part of a larger shot that's breathtaking]. The two bright "stars" are Venus and Jupiter, and you can see the glow from zodiacal light reaching up and to the left, following the ecliptic.

The origin of zodiacal light (when I learned about it, years ago) was thought to be dust from asteroid collisions. Asteroids out past Mars orbit pretty much in the same plane as the planets. When they smack into each other – and they do – they make dust. This reflects sunlight, so we’d see it as a faint band of light across the ecliptic. Case closed!

Of course, regular readers know me better than this. Read on!

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Privately and publicly looking for Earth-threatening asteroids

By Phil Plait | June 28, 2012 12:53 pm

[Note: In the interest of full disclosure, I am friends with many of the folks on both teams described below. I have tried to be scrupulously fair to both missions, and to be honest - as I say below - the best thing to happen would be for both missions to be locked, loaded, and looking for potentially hazardous rocks.]

The B612 Foundation is a group of scientists, astronauts, astronomers, and engineers who have come together to do nothing less than literally save the world: they want to find and deflect asteroids that can potentially hit the Earth. While really big asteroids are rare — after all, the one 10 km (6 miles) across that wiped out the dinosaurs only hits Earth every few hundred million years — smaller ones in the 100 meter range are far more common and can still do devastating damage. Even one just 50 meters across (smaller than a football field) can impact and explode with the yield of millions of tons of TNT. That’s in the range of the biggest nuclear weapons ever detonated.

Finding these asteroids is notoriously difficult. They’re small and dim, and sometimes only discovered once they’ve already passed us! The best way to find them in large numbers is to launch a space telescope to survey the sky, tuned to the infrared where these asteroids are far brighter and easier to spot.

Today, B612 made a big announcement: they want to build just such a mission. They call it Sentinel, and it will be the first privately funded deep space mission ever launched. Built by Ball Aerospace and launched on a SpaceX Falcon 9 rocket, it will be placed into a Venus-like orbit, giving it a good view of the volume of space where these asteroids prowl:

[Click to chixchulubenate.]

The plan is to raise the money philanthropically, like museums do: donations from private funders. Observatories have long been funded this way, and the proposed cost of a few hundred million dollars is roughly on par with many civic projects. Their target launch date is 2017 to 2018, and the mission will last about 5 years.

Interestingly, a group of scientists and engineers with NASA/JPL is planning a similar mission! Called NEOCam (for Near Earth Object Camera), it’s based on previous missions like WISE and Hubble.

Sentinel and NEOCam have many similarities: they both use a 50 cm or so telescope, both are tuned to infrared, and both will launch into orbit to get a better view of potentially threatening asteroids. Read More

Breaking: Private company does indeed plan to mine asteroids… and I think they can do it

By Phil Plait | April 24, 2012 12:01 am

Planetary Resources, Inc. is not your average startup: its mission is to investigate and eventually mine asteroids in space!

Last week, the company issued a somewhat cryptic announcement saying they “will overlay two critical sectors – space exploration and natural resources – to add trillions of dollars to the global GDP”. I predicted this meant they wanted to mine asteroids, and yes, I will toot my own horn: I was right. They’re holding a press conference Tuesday morning to officially announce they’re going asteroid hunting.

The company had a pretty fierce amount of credibility right off the bat, with several ex-NASA engineers, an astronaut, and planetary scientists involved, as well as the backing of not one but several billionaires, including a few from Google… not to mention James Cameron. The co-founders of Planetary Resources are Peter Diamandis — he created the highly-successful X-Prize Foundation, to give cash awards to incremental accomplishments that will help achieve technological breakthroughs, including those for space travel — and Eric Anderson, X-Prize board member and Chairman of the Board of the Space Spaceflight Federation.

These are very, very heavy hitters. Clearly, they’re not screwing around.

So what’s the deal?


Step 1

I spoke with Planetary Resources President and Chief Engineer Chris Lewicki on the phone Monday. He has an excellent pedigree: Lewicki was Flight Director for the NASA’s Spirit and Opportunity Mars rover missions, and also Mission Manager for the Mars Phoenix lander surface operations. So when he says he’s confident the company can and will succeed, I’m willing to listen.

“This is an attempt to make a permanent foothold in space,” he said. “We’re going to enable this piece of human exploration and the settlement of space, and develop the resources that are out there.”

The plan structure is reminiscent of that of Apollo: have a big goal in mind, but make sure the steps along the way are practical.

The key point is that their plan is not to simply mine precious metals and make millions or billions of dollars– though that’s a long-range goal. If that were the only goal, it would cost too much, be too difficult, and probably not be attainable.

Instead, they’ll make a series of calculated smaller missions that will grow in size and scope. The first is to make a series of small space telescopes to observe and characterize asteroids. Lewicki said the first of these is the Arkyd 101, a 22 cm (9″) telescope in low-Earth orbit that will be aboard a tiny spacecraft just 40 x 40 cm (16″) in size. It can hitch a ride with other satellites being placed in orbit, sharing launch costs and saving money (an idea that will come up again and again in their plans). This telescope will be used both to look for and observe known Near-Earth asteroids, and can also be pointed down to Earth for remote sensing operations.

I’ll note Lewicki said they expect to launch the first of these telescopes by the end of next year, 2013. They’re already building them (what’s referred to as “cutting metal”). They could launch on already-existing rockets — an Atlas or Delta, for example, Europe’s Ariane, India’s GSLV, or Space X’s Falcon 9.

After that, once they’re flight-tested, more of these small spacecraft can be launched equipped with rocket motors. If they hitch a ride with a satellite destined for a 40,000 km (24,000 mile) geosynchronous orbit, the motor can be used to take the telescope — now a space probe — out of Earth orbit and set on course for a pre-determined asteroid destination. Technical bit: orbital velocity at geosync is about 3 km/sec, so only about an additional 1 km/sec is needed to send a probe away from Earth, easily within the capability of a small motor attached to a light-weight probe.

Many asteroids pass close to the Earth with a low enough velocity that one of these probes could reach them. Heck, some are easier to reach in that sense than the Moon! Any asteroid-directed probe can be equipped with sensors to make detailed observations, including composition. It could even be designed to land on the asteroid and return samples back to Earth, or leave when the observations are complete and head off to observe more asteroids up close and personal.


Step 2

Once a suitable asteroid is found, the idea is not to mine it right away for precious metals to return to Earth, Lewicki told me, but instead to tap it for volatiles — materials with low boiling points such as water, oxygen, nitrogen, and so on, which also happen to be critical supplies for use in space.

The idea behind this is to gather these materials up and create in situ space supply depots. Water is very heavy and incompressible, so it’s very difficult to launch from Earth into space (Lewicki quoted a current price of roughly $20,000 per liter to get water into space). But water should be abundant on some asteroids, locked up in minerals or even as ice, and in theory it shouldn’t be difficult to collect it and create a depot. Future astronauts can then use these supplies to enable longer stays in space — the depots could be put in Earthbound trajectories for astronauts, or could be placed in strategic orbits for future crewed missions to asteroids. Lewicki didn’t say specifically, but these supplies could be sold to NASA — Planetary Resources would make quite a bit money while saving NASA quite a bit. Win-win.

The details of exactly how they’ll collect these resources and store them may be revealed in the press conference Tuesday. If I can, I’ll ask.


Step 3

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CATEGORIZED UNDER: Astronomy, Cool stuff, NASA, Space, Top Post

Space firm about to make a big announcement. I take a stab at what it is.

By Phil Plait | April 18, 2012 3:26 pm

I’m overwhelmed with work right now prepping for a half dozen different things, but I had to make some comment on a press release I just got in the mail.

Here’s the important bit [emphasis mine]:

Join visionary Peter H. Diamandis, M.D.; leading commercial space entrepreneur Eric Anderson; former NASA Mars mission manager Chris Lewicki; and planetary scientist & veteran NASA astronaut Tom Jones, Ph.D. on Tuesday, April 24 at 10:30 a.m. PDT in Seattle, or via webcast, as they unveil a new space venture with a mission to help ensure humanity’s prosperity.

Supported by an impressive investor and advisor group, including Google’s Larry Page & Eric Schmidt, Ph.D.; film maker & explorer James Cameron; Chairman of Intentional Software Corporation and Microsoft’s former Chief Software Architect Charles Simonyi, Ph.D.; Founder of Sherpalo and Google Board of Directors founding member K. Ram Shriram; and Chairman of Hillwood and The Perot Group Ross Perot, Jr., the company will overlay two critical sectors – space exploration and natural resources – to add trillions of dollars to the global GDP. This innovative start-up will create a new industry and a new definition of ‘natural resources’.

Well now, what could that mean? What natural resources are there in space? Solar energy might count, but I have a strong suspicion what they’re really talking about is asteroid mining.

Yes, you heard me. Let me be VERY clear: I’m speculating here. I have no more info on this than what I’ve quoted there, but it fits what the release says. Peter Diamandis is a big thinker, to put it mildly. His Wikipedia page should give you a taste of that. Asteroid mining is big enough for him to be interested in it! And heck, he said as much in his TED talk.

The engineering behind it would be fearsome. We’re a ways out from being able to do this, but if we had a big rocket — say SpaceX’s Falcon Heavy (though I don’t see any SpaceX folks listed in the release) — then getting an operation to a near-Earth asteroid is feasible. Even a rocky asteroid would have metals in it, and we can pick in advance one that has a higher abundance of metals. And like I said in my TED talk, we can move asteroids around if we’re patient.

If I were being optimistic, I might say something like this could get off the ground in 20 years or so, depending on several variables, and maybe sooner. Let me be frank: I don’t think this is a crazy idea.

This’ll take a lot of money… but he seems to have some fairly wealthy people — billionaires, and more than one — affiliated with this. So whatever idea he’s got, he’s being backed very seriously for it.

I have lots of other thoughts on this, but I think I’ll hold them back for now due to lack of info. The press release says the group is planning on making the announcement on Tuesday, April 24 at 10:30 a.m. PDT. It’ll be webcast, and I’ll post more info when I get it.

[UPDATE: Heh. MIT's Technology Review came to the same conclusion.]



CATEGORIZED UNDER: Astronomy, Space, Top Post

TED talks now on Netflix… including mine

By Phil Plait | March 15, 2012 1:54 pm

I just got a press release that the folks behind the TED conference have partnered with Netflix, and many of the TED talks will now be available through the online video server. That’s pretty cool!

Even cooler: my own TED talk, "How to Defend Earth from Asteroids" is one of their initial offerings! They packaged a few space talks, including mine, along with talks by Brian Cox, Carolyn Porco (that one is a must-see), Jill Tarter, and many others. There are also packages about health, biology, computers, and more.

If you are a Netflix subscriber these talks are free. I’ll note they’re all online at the TED site as well, but this may open up the talks to a bigger audience, which I think is just fine. I have Netflix, and found them easily by searching on "TED" (duh).

Not only that, but TED has a new initiative for education called TED-Ed: Lessons Worth Sharing. These are short, great educational lessons that fit well inside established classroom curricula. There are lots of such things available, of course, but these are hand-picked and will augment a teacher’s lessons. I think this is a cool idea, since TED already has a trusted brand and a wide audience. Just to be clear, there lessons are online, not on Netflix like the big talks.

If you don’t have Netflix, well, like I said you can find these talks on the TED website. And because why not, here’s mine. Enjoy:

[You may need to refresh the page to get the video to load.]

Related Posts:

- My asteroid impact talk is now on TED!
- TED x ME
- Asteroid 2011 AG5: a football-stadium-sized rock to watch carefully
- Repeat after me: Apophis is not a danger!

Like asteroid, like moon

By Phil Plait | October 5, 2011 9:00 am

The other day I posted a great picture of Saturn and its rings taken by Cassini. While digging around in my archives looking for other posts about the rings, I found one from earlier this year that had a picture of the icy moon Enceladus with the rings in the background. When I saw the picture, I got a jolt: there was a crater chain on the surface that looks just like the one on the asteroid Vesta!

Here’s a side-by-side comparison:

Enceladus is on the left, Vesta on the right (click those links for higher-res shots). Pretty cool, huh? You can see both have two big overlapping craters of roughly the same size, and a smaller third one roughly aligned on top. The set on Vesta is nicknamed — for obvious reasons — "Snowman".

Craters like this form when the impacting object is not a single body; for example, many asteroids are known to be binaries, with both objects about the same size. Getting hit by that would leave two craters either very close together or overlapping, depending on the sizes, distances, and velocities of the impacting bodies.

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CATEGORIZED UNDER: Astronomy, Pretty pictures


By Phil Plait | April 14, 2011 10:42 am

Last weekend I was in NYC attending the Northeast Conference on Science and Skepticism, aka NECSS. It was a lot of fun, as I kinda figured it would be. Skeptic conferences usually are! And of course it was a chance to catch up with a lot of old friends.

Attendees are writing their opinions of the meeting all over the place (like here, here, and here for starters). I’ll spare you the recap, which would boil down to how awesome my talk was, and cut to the chase which is to thank Michael Feldman from the New York City Skeptics, and all the folks from the New England Skeptical Society for inviting me and throwing such a fab conference.

I’d be remiss, though, if I didn’t include this little bit of funnery. Skeptical singer songwriter and BA friend George Hrab was at NECSS. On Geo’s last album, "Trebuchet", he wrote a tune called "Death from the Skies" — based on the brilliant book of the same name. He plays the funky beat, and I read statistics of getting killed by various astronomical events. We performed this song live both at Paddy Reilly’s, a bar where Geo had a gig, and to close out the ceremonies.

Here’s the recording of the latter, which is pretty laid back considering how many octillions of Joules of energy I’m talking about:

And what the heck, here we are at the somewhat more rambunctious bar the night before:

See? If you go to skeptic meetings you can experience stuff like this live. It’s way too much fun.

There are photos of NECSS popping up all over the place (search Flickr), including for example a nice set by Bruce Press. I also like this shot of Geo and me taken by Brian Engler. Apparently I had just stubbed my toe.

NECSS really is a terrific event. I hope to see you all there next year!

Ashes to ashes, stardust to stardust

By Phil Plait | April 12, 2011 7:00 am

On March 24, the NASA mission Stardust ran out of fuel and sent its last data to Earth. At 16:33 Pacific time the mission was officially ended.

Launched in 1999, Stardust became a wildly successful mission. It passed by the asteroid Annefrank, sampled the dust from one comet (Wild 2) — returning those samples to Earth in a special re-entry container while the spacecraft itself flew on — and looked closely at another (Tempel 1) to see the crater left by the Deep Impact mission.

It’s always sad to see a mission end, but I like to also keep my eyes ahead. Stardust may be done, but Rosetta flies on, heading toward a rendezvous with a comet where it will deploy an actual lander. The Dawn spacecraft will enter orbit around the main-belt asteroid Vesta later this year as well. And, of course, MESSENGER is now orbiting Mercury and returning data.

We learned a lot from Stardust, and we get better with this endeavor of solar system exploration as a result.

And that’s the whole point, isn’t it?

Image credit: NASA/JPL-Caltech

Related posts:

- Followup: Deep Impact crater on Tempel 1
- Stardust snaps close-ups of a second-hand comet!
- A comet creates its own snowstorm!
- The return of Stardust
- Stardust@Home starts NOW



By Phil Plait | March 31, 2011 12:30 pm

I have a new article up on Blastr, the SyFy channel’s web site for news and info and scifi-y stuff.

The article is about asteroid impacts, and the lack of Hollywood accuracy thereof. I take a typical movie synopsis and destroy it plot device by plot device. It’s like taking all my movie reviews and condensing them down into one run-on snark.

And yes, I know that the illustration for the article (seen here) is scientifically inaccurate. I know what you’re thinking; it’s so obvious: no asteroid is actually flying saucer shaped! At least, that’s what they want you to think*.

So go over there, read the article, and leave your own complaints in the comments. I promise I will read them all and take them into consideration.

* Dear readers with an impaired sense of humor: I know that’s not really how the picture is scientifically inaccurate. Of course, the actual mistake is that you should see thousands of stars in the background.

No I won’t.

Related posts:

- Blastr: Other than that, Spock, how was the movie?
- Blastr: I Was A Zombie For Science
- Big budget movies that got their science right
- Master of Blastr

MORE ABOUT: asteroids, Blastr, SyFy

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