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Massive Volcanic Eruptions Accompanied Dinosaur Extinction

Convector Re:Antipodal eruptions (78 comments)

I've never found the antipodal argument convincing. Seismic waves converge at the antipode of an impact only if the target is spherically symmetric and isotropic. In the actual Earth, you have reflections off all kinds of laterally varying boundaries. Also, the sound speed differs substantially between continental and oceanic crust, so the path matters quite a bit.

The Chixulub impact is also not that big (as planetary-scale impacts go). The projectile was what, 10 km? Shock heating is only significant within a few times the projectile diameter.

about a month ago

Scientists Have Finally Sampled the Most Abundant Material On Earth

Convector Re:What's wrong with calling it (128 comments)

It's not liquid, it's not hot, and it's not magma.

about 2 months ago

President Obama Backs Regulation of Broadband As a Utility

Convector Re:Obama (706 comments)

To be fair, this is basically what's happening.

about 3 months ago

Underground Experiment Confirms Fusion Powers the Sun

Convector Re:Underground? (141 comments)

It goes down every day on its own. They just went way out west and built the lab in the spot where the Sun sets.

about 5 months ago

Teaching College Is No Longer a Middle Class Job

Convector Re:Administrators (538 comments)

What's in your wallet?

about 7 months ago

Draper Labs Develops Low Cost Probe To Orbit, Land On Europa For NASA

Convector Phase I study (79 comments)

It's not clear from the summary (or the linked article), but this isn't a mission at this point. This is a concept selected for Phase I study.

From the NASA Innovative Advanced Concepts (NIAC) news release:
"NIAC Phase I awards are approximately $100,000, providing awardees the funding needed to conduct a nine-month initial definition and analysis study of their concepts. If the basic feasibility studies are successful, proposers can apply for Phase II awards, which provide up to $500,000 for two more years of concept development."

This effort is independent of the ongoing Europa mission studies (e.g. the Clipper concept.) The Draper concept may end up getting a mission if the results prove promising. Personally, I have doubts that this will prove credible, but that's the whole point of the NIAC studies.

about 7 months ago

Saturn May Have Given Birth To a Baby Moon

Convector Re:The Birth of a Moon... (71 comments)

Not the whole ring system. Only the A-D rings are within the Roche limit. But the phenomenon discussed here is happening in the A-ring, so this limitation does indeed apply. I don't understand how a moon could accrete here.

about 9 months ago

Stephen Colbert To Be Letterman's Successor

Convector Re:WTF? (193 comments)

Actually, I always had wanted Stewart cast as Denethor. Not only could he have played the character much closer to how he's portrayed in the book, he'd have been a great foil to McKellen's Gandalf.

about 10 months ago

Job Automation and the Minimum Wage Debate

Convector Re:hmmm (870 comments)

Well, at least the Canadian pennies should stop being such a problem. They stopped making them a couple years ago. http://www.cbc.ca/news/canada/...

about 10 months ago

Quarks Know Their Left From Their Right

Convector Re:We are not an audience (150 comments)

A prolate spheroid doesn't taper to points on the end. You'd need an infinite series of spherical harmonics to describe an American football, not just the degree-2 term. Though it's sufficiently elongated that spherical harmonics might not be the best basis set. Bessel functions?

about a year ago

Americans To FCC Chair: No Cell Calls On Planes, Please

Convector Re:213 times? (340 comments)

Well, you have to admire the restraint, but I think this calls for a more forceful protest.

1 year,12 days

Bill Nye To Debate Creationist Museum Founder Ken Ham

Convector Re:Waste of Time (611 comments)

Like how Jor-El sent his only son to Earth to save mankind?

1 year,26 days

US Customs Destroys Virtuoso's Flutes Because They Were "Agricultural Items"

Convector Re:Saw this earlier (894 comments)

I'd also be confused if this site were in my current directory.

1 year,27 days

Get Ready For a Streaming Music Die-Off

Convector Re:The article is FUD (370 comments)

It's always bothered me when a radio program is called a "show". What exactly are you showing me?

about a year ago

Should companies start using drones for common tasks, like package delivery?

Convector Package Delivery? (378 comments)

They should have used Planet Express!

about a year ago

MAVEN Ready To Launch Today

Convector Re:Pretty easy to speculate... (55 comments)

A few points of clarification.

1. The major heat-producing elements are all lithophiles, preferentially bounding to silicates. So there's virtually no radioactive decay in the core. It's all in the crust and mantle.

2. Thorium is an important heat source now due to its long half-life (14 Gy IIRC). But back in the day, Uranium and Potassium-40 were much more abundant, and produced the majority of the radioactive heating.

3. Assuming the Earth and Mars initially had similar bulk compositions, they would have similar rates of radioactive heating. But Mars surely cooled more quickly. The heat production scales as the mass, and therefore the volume. Heat loss scales as the surface area. So smaller planets have the lower surface to mass ratio and cool more quickly.

about a year ago

MAVEN Ready To Launch Today

Convector Re:Pretty easy to speculate... (55 comments)

Earth already had its iron core at the time of the Moon forming impact. Most of the impactor accreted onto the Earth and the cores of the two bodies merged (Canup and Asphaug, 2001, Nature). A fraction of the silicate crust and mantle of the impactor and target was ejected into orbit. That debris accreted into the Moon. Since it is largely made of the silicate portion of the original bodies, it is depleted in metal, and has a relatively small core.

about a year ago

Hotel Tycoon Seeks Property Rights On the Moon

Convector Re:It's quite impractical, I'm afraid... (248 comments)

That's actually not an error. It's a contraction of "Space September", the name of a time unit in the early attempts at a Space Calendar or "Spalendar" that wouldn't be tied to solar or lunar cycles as viewed on Earth. It never caught on, which is too bad, because "Spock-tober" would be awesome.

about a year ago


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