CLOSE
Original image

Collision Course: A Brief Guide to Earth's Most Interesting Impact Craters

Original image

A Norwegian family arrived at their cabin to open it up for the spring and found a surprise: a large rock had smashed through the roof. It was identified as a 1.3 pound breccia meteorite. It didn't hurt anybody, and its sale price should easily cover the damage to the roof; meteorites are valuable to collectors. But although most meteorites are very small, and to date nobody has been more than bruised by one, some of them are big and make a violent impression where they hit. Here are a few of the more interesting impact craters around:

Barringer Crater, Arizona, USA


View Larger Map

Also known as "Meteor Crater," this was the first crater identified, due to its relatively pristine appearance. It's young, as craters go -- just 50,000 years old -- and it was created by a nickel-iron meteorite about 50 meters across, excavating a crater about 1.2 km across.

Obolon' Crater, Poltava Oblast, Ukraine


View Larger Map

Not all craters are so obvious; sometimes their structure is only apparent in aerial views. Obolon' Crater was detected from the presence of shocked minerals in the surrounding, a tell-tale sign of an impact event. It's 20 km across and is estimated to be about 169 million years old, though there is some evidence it may be quite a bit older. (More on that next.)

Manicouagan Crater, Quebec, Canada


View Larger Map

Visible from space as a ring-shaped lake, this 100 km multi-ringed crater (with a 70 km central ring that is now Manicouagan Reservoir) was created by the impact of a 5km asteroid about 216 million years ago. What's interesting about this crater is that, if you account for plate tectonics and then roll the clock back about 216 million years, this crater has an eerily precise alignment with several other craters: Rochechouart in France, St. Martin in Manitoba, Obolon' in the Ukraine, and Red Wing crater in North Dakota. All of these craters may have been produced by a meteor train, the result of an object breaking up due to tidal forces or collisions.

Gosses Bluff Crater, Northern Territory, Australia


View Larger Map

What's left of this one is only 5 km across, but that's really only the central uplift that is found in some larger craters; the outer rim has mostly eroded away. This crater dates back about 142 million years. The local Aborigines regard it as sacred and, interestingly, give it an origin story hinting at its true origins: their story is that the child of the morning and evening stars fell out of the sky and hit the Earth in this spot; the shape of the bluff is evocative of its origin.

Karakul Crater, Pamir Mountains, Tajikistan



View Larger Map

This relatively young crater (between 5 and 25 million years old) is in Tajikistan and features a large lake at its center. The overall depression is 52 km across.

Sudbury Basin, Ontario, Canada



View Larger Map

This highly elliptical and also frighteningly large impact crater is difficult to see; it is shallow (the blow was a glancing one) and is heavily eroded and largely covered in vegetation. There is a large lake at one end, and the shape of it is crudely visible as human settlement has been mostly in the valley. The impactor would have been about 10-15 km in size, and struck the Earth about 1.849 billion years ago.

Vredefort Crater, Free State Province, South Africa


View Larger Map

Sudbury is big, but it's not the biggest. At 300 km across, Vredefort is the biggest confirmed impact crater on Earth. It's also the second oldest, at a little over 2 billion years of age. This impactor was probably 5-10 km, but traveling on a more direct course than the one that created Sudbury.

Chicxulub Crater, Yucatan, Mexico

This is not the largest crater on Earth, and you cannot see it at all from the surface. But it's one of the most famous, because this is the one widely suspected to have done in the dinosaurs. It's 180 km across, and the impactor is believed to have been at least 10 km across, striking Earth with a force of roughly 96 teratons of TNT. Geologic evidence indicates that the region was completely underwater at the time, and it would have produced a phenomenal tsunami.

[Gravity map created from public data by Milan Studio and released through Wikimedia Commons.]

Original image
AFP/Stringer/Getty Images
arrow
Space
SpaceX's Landing Blooper Reel Shows That Even Rocket Scientists Make Mistakes
Original image
SpaceX's Falcon 9 rocket launches.
AFP/Stringer/Getty Images

On March 30, 2017, SpaceX did something no space program had done before: They relaunched an orbital class rocket from Earth that had successfully achieved lift-off just a year earlier. It wasn't the first time Elon Musk's company broke new ground: In December 2015, it nailed the landing on a reusable rocket—the first time that had been done—and five months later landed a rocket on a droneship in the middle of the ocean, which was also unprecedented. These feats marked significant moments in the history of space travel, but they were just a few of the steps in the long, messy journey to achieve them. In SpaceX's new blooper reel, spotted by Ars Technica, you can see just some of the many failures the company has had along the way.

The video demonstrates that failure is an important part of the scientific process. Of course when the science you're working in deals with launching and landing rockets, failure can be a lot more dramatic than it is in a lab. SpaceX has filmed their rockets blowing up in the air, disintegrating in the ocean, and smashing against landing pads, often because of something small like a radar glitch or lack of propellant.

While explosions—or "rapid unscheduled disassemblies," as the video calls them—are never ideal, some are preferable to others. The Falcon 9 explosion that shook buildings for miles last year, for instance, ended up destroying the $200 million Facebook satellite onboard. But even costly hiccups such as that one are important to future successes. As Musk once said, "If things are not failing, you are not innovating enough."

You can watch the fiery compilation below.

[h/t Ars Technica]

Original image
NASA/Getty Images
arrow
Space
Here's Where You Can Watch a Livestream of Cassini's Final Moments
Original image
NASA/Getty Images

It's been a road trip like no other. After seven years and 2.2 billion miles, the NASA orbiter Cassini finally arrived at the Saturn system on June 30, 2004. Ever since, it's been capturing and transmitting valuable data about the distant environment. From sending the Huygens probe to land on the moon Titan to witnessing hurricanes on both of the planet's poles, Cassini has informed more than 3000 scientific papers.

It's been as impressive a mission as any spacecraft has ever undertaken. And tomorrow, Cassini will perform one last feat: sacrificing itself to Saturn's intense atmosphere. Project scientists are deliberately plunging it into the planet in order to secure just a little more data—and to keep the spacecraft, which is running low on fuel, from one day colliding with a Saturnian moon that might harbor life.

Because it won't have time to store anything on its hard drive, Cassini will livestream its blaze of glory via NASA. The information will be composed mostly of measurements, since pictures would take too long to send. Instead, we'll get data about Saturn's magnetic field and the composition of its dust and gas.

"As we fly through the atmosphere, we are able to literally scoop up some molecules, and from those we can figure out the ground truth in Saturn’s atmosphere," Scott Edgington, a Cassini project scientist, told New Scientist. "Just like almost everything else in this mission, I expect to be completely surprised."

The action will kick off at 7 a.m. EDT on Friday, September 15. Scientists expect to say goodbye to Cassini less than an hour later. 

While you wait for Cassini's grand finale, you can check out some essential facts we've rounded up from Saturn experts. And keep your eyes peeled for a full recap of Cassini’s historic journey: Mental Floss will be in the control room at the Jet Propulsion Laboratory in Pasadena, California, to offer a firsthand account of the craft's final moments in space. 

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios