For the Avengers, the intergalactic threat of “Infinity” has faded. In issue #24.NOW, the suitable new jumping-on point for author Jonathan Hickman’s heady series, the team allows themselves to momentarily relax with target practice and beer pie. But in the Marvel Universe, there is no rest for the heroic! A new danger from space emerges.

As far as sci-fi storytelling goes, the idea’s not as crazy as you might think.

A Universe of Projectiles

“Rogue planets,” massive objects that hurtle through the vastness without a gravitational tether, have been theorized to exist since at least since the 1990s, but examples could not be confirmed until recently. Observation of the nomads can be performed via gravitational lensing measurements, when the flicker of a star’s light is distorted as the body passes through our view of it, which is a tough task if you don’t already know what you’re looking for. Two of the most publicized recent identifications, those of the wanderers dubbed CFBDSIR2149 and PSO J318.5-22, were accomplished by detecting their faint, infrared heat signatures. Now at least one study suggests that rather than being unusual anomalies, rogue planets may actually outnumber their “traditional” counterparts 100,000 to 1.


Artist’s conception of PSO J318.5-22, thought to be “only” six times the size of Jupiter.

Despite the nomenclature, though, using the term “planet” to describe these curiosities isn’t quite right, for a few reasons. Everyone remembers the academic brouhaha when Pluto was “demoted” from planetary status in our solar system to just a lowly Kuiper Belt Object. That was due to the fact Pluto doesn’t meet the refined definition of “planet,” something that clears other objects out of its orbital path. Since the rogues don’t have designated orbits, they can’t technically be called planets, even if they were born ordinarily and later ejected from their home system. Some might have formed in interstellar space, never having the pleasure of being a true planet, and others might actually be low-mass brown dwarf stars.


Artist’s depiction of a brown dwarf, which is much larger than a gas giant planet, but just small enough that it can’t achieve the nuclear fusion that powers more familiar stars. Image from dailygalaxy.com

Collision Course

Upon learning that the Earth is square in the crosshairs of an oncoming rogue planet, the ever suspicious Hawkeye concocts a neat conspiracy theory about a culprit.

Well, not really. Space is mostly empty. Like, really, really empty. About a million particles per cubic meter, whereas the number of particles in the same volume of Earth’s atmosphere is a number with 25 zeroes at the end. So there aren’t many sources of friction to alter an object’s course. A rogue isn’t likely to be influenced by the gravitation of stars, either, as the average distance between the fiery furnaces is over 4,000 light years. A straight line in space is fairly natural.


It’s called the “void” for a reason.

But given how empty space is, isn’t a little too coincidental that the murderous mass is pointed right at us? Yes and no. Taken in a vacuum (vacuum—space—get it?), the odds might seem long, but you have to consider that the universe is also really, really big. Maybe even infinitely so. Almost as many stars just in the observable portion as there are particles in a cubic meter of Earth’s atmosphere.

So if you mash those two enormities together, you’re bound to find a planet somewhere that happens, just by chance, to be the target of a celestial body gone wild. Why Earth? Why not? To say that just because something is screaming toward us we must have been targeted is like some kind of reverse anthropic principle; the universe has been fine-tuned for DEATH.

Yet it is staggeringly unlikely, which made the Nibiru nonsense of 2012 all the more silly. As one of the myriad doomsday predictions of that year, plenty of paranoid people imagined a celestial juggernaut named Nibiru bearing down on us from the great beyond. NASA senior scientist David Morrison, who hosts an “Ask an Astrobiologist” column on the organization’s website, had to field upwards of 25 questions about the figment every week in the years leading up to the non-apocalypse.


Artist’s depiction of…absurdity. Sorry, doomsday preppers.

The Nibiru myth had its roots in the alien abductee subculture, and like the UFO mystery-mongers, Nibiru neurotics eventually began to claim that NASA and the world’s governments were covering up the destroyer’s existence. The Avengers had to be told of their rogue’s presence by a future descendant of Tony Stark. We probably wouldn’t have that problem. An object four times the size of Earth, as proponents often described it, would be visible not only to every amateur astronomer with a telescope, but even to the naked eye. I mean, could NASA hide the existence of Mars? Really.

It Gets Worse.

So you can breathe easy that we likely won’t be facing an extinction level threat from a rogue planet anytime soon. I probably shouldn’t mention there are hypervelocity stars zipping around our galaxy, too. We’ve seen at least 16, moving at 2 million miles per hour, which have likely been slingshotted by the titanic gravity of Sagittarius A*, the supermassive black hole at the center of the Milky Way. Oh, and I really shouldn’t say anything about the black holes that themselves go crashing through galaxies.


A runaway supermassive black hole looks to be ruining the days of any inhabitants in the CID-42 star system.

Maybe that’ll be the next conspiracy theory. “Of course you can’t see it, IT’S BLACK! Wake up, sheeple!”

About The Author

Russ Dobler
Contributor

Better known as "Dog" to friends and weirdos, Russ is a wannabe scientist who wears a safety vest instead of a labcoat. He writes about why science is important and how it's done at What Does This Mean? and drinks beer wherever he can find a nice tap selection.

  • David Brooke

    Great article. Loved every line of it!

  • Icenein

    I’m not sure where your figure of 4000 light years being the average distance between stars comes from. There are thousands of stars within 4000 light years of the sun. Heck, there’s a star less than five light years from the sun.

    • Russ Dobler

      Thanks for that note. I was using a figure quoted in articles such as this one:

      http://www.itwire.com/science-news/space/57280-astronomers-find-average-distance-between-stars

      Looking at it again, it seems they’re including the space between galaxies in that calculation, which is kind of misleading. You’re totally right that in our region of the Milky Way, the distance between stars is usually between 3 and 5 light years. Still far enough to support the concept, but THREE orders of magnitude off! Yikes!

      Thanks again for pointing that out.