NASA Flyover and Tour of Asteroid Bennu

NASA has created a couple of flyover/tour animation videos of asteroid Bennu, which was explored by the OSIRIS-REx spacecraft.

When NASA’s OSIRIS-REx spacecraft arrived at asteroid Bennu in December 2018, its close-up images confirmed what mission planners had predicted nearly two decades before: Bennu is made of loose material weakly clumped together by gravity, and shaped like a spinning top. This major validation, however, was accompanied by a major surprise. Scientists had expected Bennu’s surface to consist of fine-grained material like a sandy beach, but instead OSIRIS-REx was greeted by a rugged world littered with boulders – the size of cars, the size of houses, the size of football fields.

CNN–Clickbait Network News

Twitter user Peter Hague recently noticed a fairly typical example of how CNN has become little more than a clickbait site at times, with almost no quality control in the articles it publishes.

The article in question concerns a tweet that Elon Musk sent about an asteroid that will make a near-Earth approach in 2029.

The CNN headline blasts Musk for hyping a non-existent threat,

Despite Elon Musk’s alarmist tweet about an asteroid hitting Earth, NASA says there is no known threat

Ugh. Elon’s at it again talking crazy. So what did Musk say? According to the first three paragraphs, Musk apparently tweeted that an asteroid is going to hit the Earth even though NASA disagrees,

Elon Musk, CEO of SpaceX and Tesla, tweeted that a “big rock” is going to hit Earth, and that we “currently have no defense.”

But NASA, seems to disagree.

Musk’s tweet was a response to another by comedian and podcaster Joe Rogan, who shared an article reporting that NASA has begun preparations for the 1,100-foot-wide asteroid Apophis, which is scheduled to pass by Earth on April 13, 2029. Apophis named after an Egyptian god of death.

Jesus, Elon, stop scaring people into thinking Apophis is going to hit the planet. Lets go to Twitter and reply to his tweet to that effect.


So Joe Rogan made a tweet about Apophis, and Elon Musk retweeted him in order to add that this particular asteroid poses little threat to the Earth but that “a big rock will hit Earth eventually & we currently have no defense.”

Don’t worry, though, CNN’s Leah Asmelash isn’t going to let the facts get in her way.

Musk didn’t elaborate on what he meant by “big rock,” so it’s hard to know what he was actually referring to.

NASA’s website, though, clearly says, “No known asteroid poses a significant risk of impact with Earth over the next 100 years.”

Apparently Asmelash’s editors are fine with her rewriting “eventually” into “within the next 100 years by a currently known asteroid.” As the NASA website that she links to notes (but she omits), there are known asteroids that do have a significant risk of hitting the earth in the next 200 years (and by significant, we’re talking about less than .2 percent). And, of course, there are asteroids that we do not know about.

Large objects have hit the planet during the time that homo sapiens have existed, including the Arizona Meteor Crater which was created 50,000 years ago by a meteor estimated to be 60 meters in diameter. According to NASA estimates, that impact released the equivalent of 15 million tons of TNT–equivalent to a small hydrogen bomb (most US nuclear weapons, in contrast, have only about 500 kiloton yields).

Similarly, Asmelash hits out at Musk’s claim that we have no defenses, but the best she can muster is,

“While no known asteroid larger than 140 meters in size has a significant chance of hitting Earth for the next 100 years, NASA and its partners are studying several different methodologies for deflecting a hazardous asteroid,” he said.

Basically, even if an asteroid were hurtling toward Earth, scientists believe they will have the technology to deflect it off course and prevent collision.

Rather than try to illuminate or educate about the potential risks from asteroids and the costs/difficulties in actually doing anything about it, Asmelah apparently saw a chance to write a clickbait story about an “alarmist tweet” that exists entirely in her own story’s mischaracterization of it.

Shame on CNN for this sort of nonsense.

Saving the Planet from an Asteroid

New Scientist magazine reports on studies examining the feasibility of different methods of dealing with asteroids on collision course with Earth.

New Scientist has an interesting look at research into the best way to stop an asteroid on a trajectory for a deadly impact with the Earth.

To investigate the best way to deflect this and other asteroids onto a harmless path, a team led by David Dearborn of the Lawrence Livermore National Laboratory in California has modelled the impact of a nuclear explosion on an object’s trajectory. Their virtual asteroid was 1 kilometre in diameter and made of rocky rubble loosely bound together by gravity, which is considered by many planetary scientists to be the most likely composition for small asteroids.

Typically the “nuke the asteroid” scenario is ridicule on a number of grounds, but Dearborn found if you can get to the asteroid soon enough — in his model, 30 years prior to the projected impact with the Earth — a 100 kiloton nuclear blast 250 meters behind the asteroid was quite effective at altering the asteroid’s trajectory so it missed the Earth. The nuke in the model did cause about 1 percent of the asteroid to break off, but only 1 part in  a million of that debris was still headed on a collision course with the Earth.

And, of course, unlike a lot of other techniques that have been proposed for steering deadly asteroids off of a collision course is that we actually have nukes sitting around and quite a bit of experience using them.

The New Scientist piece does look at some of these other proposals, including an intriguing one using satellite-based lasers to vaporize small section of an oncoming asteroid. That would create a plume of gas that would then propel the asteroid on a slightly different path, hopefully altering it enough to keep it from impacting the Earth.