Artist’s Impression

Speaking of space and asteroids. Here is one image I see over and over again. It’s driving me insane.

Splash!

You will see it in every second science article on the extinction of dinosaurs or meteorites. Like this Wired article for example. It’s one of the so-called “Artist’s Impressions”. They often accompany scientific articles to illustrate a certain point. This particular one turned out to be especially virulent as it’s been used over and over again. It seems to have been made by Don Davis who has been painting similar motifs for some time. It’s attractiveness is obvious. Especially the scale is awe-inspiring. You can see the asteroid towering miles above the atmosphere as it embedding itself in the soft crust of planet.

… but wait. ABOVE the atmosphere? That sounded suspiciously large to me. So I began to crunch some numbers. Follow me on this one.

Estimate of the size of the depicted asteroid.

Judging by the curvature of the earth the depicted asteroid should be around 1000km in diameter. This is just a rough estimate since the perspective on the painting can’t be accounted for due to lack of reference points. It’s still way larger than the 300 miles mentioned in the Wired article. In fact 1000km is ridiculously huge. Let’s get some context.

Comparission of the depicted asteroid, the second-largest object in the asteroid belt and an asteroid roughly the size of the one that could have caused the extinction of the dinosaurs.

1000km diameter is even slightly larger than the size of Ceres, the largest asteroid in the Solar System. And Ceres itself is so large that in fact, it’s classified as a “Dwarf Planet” instead of an asteroid. The above image shows Vesta in comparison, which I was talking about previously. It’s the second largest object in the asteroid belt and only about half the diameter of the depicted asteroid.

So the depicted asteroid is actually larger than the largest asteroids that exist today. This sounds a bit dubious already. But how does the depicted impact compare to the one that wiped out the dinosaurs. Well on the far right of the image, you might see a tiny dot. That’s how big Gaspra a 12km diameter asteroid would look like. This is around the size of the object that caused the Chicxulub crater which is a good match for the impact that might have caused the extinction of the Dinosaurs.

But there is more. Another thing that rubs me the wrong way is how calm and serene the scene looks like. It’s like trowing a pebble in a pond. What would you REALLY see if you were to observe an impact so large from space. Well, we have observed quite large impacts already. Here is what an impact of an object on Jupiter looked like.

We observed a lot of object impacts on Jupiter. The above here is from 2010. It’s remarkable because it shows the actual impact flash. And that’s pretty much all you can see in an asteroid impact. A flash. The tiny dot on the left of Jupiter is a bright explosion the magnitude of up to 1 Megaton. An average-sized H-Bomb. It appears as such a tiny dot because Jupiter is many times larger than Earth. It’s quite remarkable that you can see it at all from that far away. Trust me, it’s a huge, bright explosion that would easily wipe out any major city on Earth.

The thing is, asteroid impacts are incredibly powerful not only because of the mass of the asteroids, but also because of their speed. An average meteor impacts Earth with the speed of 10-70 km/second. That between 30 and 200 times the speed of sound. At these speeds, even relatively small objects pack a huge amount of energy. And sure enough, that H-Bomb on Jupiter was caused by an asteroid around just 10m across! That’s 1000 times smaller than the dinosaur asteroid. 100,000 times smaller than the depicted one. The impact of an asteroid 1000km across would cause a flash so bright it would out-shine anything you see. Instead of the impact causing a tidal wave like on the painting, the light of flash itself would probably bright enough to vaporize seawater. Imagine a small, blinding bright sun burning on surface of planet Earth. Indeed, you would need to use a dark eye filter – similar to the ones used to watch solar eclipses – in order to even look at the impact and not hurt your eyes.

Needless to say, the painting is laughable. It’s an exaggeration and underestimation at the same time. It exaggerates the size of the actual impact body while hopelessly underestimating the power of such impacts. An artist’s impressions should fuel the audience’s imagination, it shouldn’t lead it astray. It’s a pretty illustration for a Sci-Fi story. But every time I see this particular painting in a scientific article, I want to trow an asteroid on the author myself.