Space Junk

In 2013, director Alfonso Cuarón came out with Gravity, a movie about junk. Specifically, it's a movie about space junk.

In the film, a missile strike on a satellite results in a runaway chain reaction of collisions between space junk and satellites. This brings down space stations, satellites, and spacecraft left and right, rendering Earth's orbit useless to manned travel. 

Gravity is an excellent movie, and we’ll forgive a few scientific inaccuracies, since they're all in service of the plot. (Neil Degrasse Tyson, despite his multiple criticisms of the science, is a fan of the film.)

The threat in Gravity is a very real one. It's a scenario known as Kessler Syndrome, where space debris collides with space debris, generating more space debris, which collides with yet more space debris, until that specific orbit around Earth is so filled with debris that it is rendered nearly useless for human purposes. (Low Earth orbit is the most likely orbit to be lost to this process, though geosynchronous orbit is another possible victim.)

It's not astonishing that this is a serious concern for NASA and other space scientists. There are more than 2,000 satellites in orbit, about 1,500 of which are operational, along with nearly 18,000 trackable artificial objects.

Smaller objects are even more common—at least 29,000 chunks of debris in orbit that are more than 10cm in size, nearly 700,000 between 1-10cm in size, and 170 million chunks of debris below 1 cm in size.

Even with how spacious Earth's orbit is, there's a very high chance of impact, and at least one satellite is destroyed by debris every year. Space junk is a serious threat even if it doesn't trigger Kessler Syndrome.

Steps are being taken to combat the risk. We're tracking debris much more carefully than ever right now. The International Space Station and other spacecraft have special protective layers known as Whipple shield: instead of building hulls out of thicker material, engineers add an extra thin layer some distance over the regular hull. The layer isn't meant to stop the debris but to break it into smaller chunks. In essence, Whipple shield turns debris from a bullet into birdshot. It even makes the needed thickness for the inner hull much smaller, so overall spacecraft mass is actually reduced.

And this: we’re developing a technology known as a laser broom. Targeting a laser on debris will heat up one side of the debris. The resulting heat emissions will then alter and destabilize the debris' orbit, causing it to burn up in the atmosphere.

Like me, trying to make pizza.

Not Really a Cliff-Diver

When you describe people as “behaving like lemmings,” most of us know what you mean (unless they're one of my grandchildren, who thought the word was “lemons”).

You're saying that the people are getting overwhelmed by mob mentality and preparing to launch themselves off a (let’s hope metaphorical) cliff because the rest of the crowd is doing likewise. Lemmings regularly commit mass suicide by jumping off cliffs, so it's a good metaphor, right?

Well, that's not exactly what lemmings do.

Beware of Humans

There's one field of geology notably unrepresented at the United States Geological Survey: paleontology. This seems like a fairly major omission, and it's all thanks to a series of events known as the Bone Wars.

During the Gilded Age (the last thirty years or so of the 1800s in America), paleontology was an incredibly competitive field. At the time, we collected dinosaur fossils more rapidly than ever before. Two figures stood out above all the rest—Edward Drinker Cope, of the Academy of Natural Sciences of Philadelphia, and Othniel Charles Marsh.

Marsh and Cope began as friends when they first met in Berlin (Germany has always been a paleontological treasure trove), but their relationship began to sour quickly. By the early 1870s, things heated up to an absurd degree. A series of mishaps, oddities, and minor snubs, along with the fundamentally incompatible personalities of the two men, irrevocably ruined things between them.

In 1873, the Bone Wars began in earnest. The first shots fired were academic ones: renaming and reclassifying species to mess with the other, publicly pointing out one another's errors, and the like.

If things had stayed like that, it wouldn't have made history the way it did; academic rivalries are, as they say, a dime a dozen. However, the confrontation escalated rapidly from there.

Marsh and Cope began hiring employees away from one another, bribing officials to advantage themselves and hurt the other, stealing fossils from one another's sites, and so on and so forth. They actively tried to destroy one another's reputations, and even turned to destroying fossils rather than letting the other get his hands on them. Financially and professionally, the rivalry eventually ruined both of them, and they never abandoned it.

The two scientists discovered 136 new species during the Bone Wars, including Triceratops and Stegosaurus. (Before then, we had only nine named species of dinosaur in North America.)

Unfortunately, the Bone Wars also did much to damage the reputation of American paleontology. It resulted in the loss of numerous fossils, the USGS losing its paleontology division, and a severe, decades-long blow to the reputation of American paleontology.