A Blast (of Gas) from the Past

Dino Gas


Imagine you’re a Trogdorian, living on the planet Trogdor seventy-five light years from Earth. It is ninety million years ago, and your planet has just developed the technology to survey nearby worlds for signs of life.

You train your ultra-sensitive space telescope on a pretty solar system with a yellow star and eight smaller worlds stretched out like gemstones on a necklace. One of these worlds, third from its star, lies at a distance where liquid water might exist on its surface. Intrigued, you set your spectroscope to examine the atmosphere (if any) of this orbiting rock.

“Holy parsec!” you exclaim. “What’s with all the methane? That planet must smell like, well, like someone’s been very rude.”

Methane gas (what we often call “natural gas”) is itself colorless and odorless. However, methane is the main ingredient in flatulence (yes, I said it). It’s the other materials mixed in with the methane that give body gas its distinctive odor. But if a planet is loaded with methane, odds are good that the methane (and the stink) came from creatures, um, blowing their own horns.

Excited by this discovery, you decide to take a closer look. When you imagine the surface of what your colleagues are now calling the “Planet of the Stench”, you soon discover the major source of the methane – creatures with long necks, tiny heads, and four thick legs holding up enormous barrel-like bodies. These creatures are near perfect eating machines, munching ceaselessly on the plants all around. And of course what goes in must come out. The Mystery of the Methane is solved! Knowing the olfactory sensitivities of your fellow Trogdorians, you rate this planet “DNVM” (Do Not Visit – Malodorous) and continue with your survey.

Could this imaginary scenario really have happened? Might our Earth be on permanent nasal quarantine? Well, it is true that methane is a great indicator of biological activity. Were aliens to image the Earth today, one of the first signs of life from our planet (besides our copious radio and television signals) would be the methane in our atmosphere, produced in part by the one billion cattle that call our Earth home. Ninety million years ago, in the Mesozoic Era, nearly as many long-necked sauropod dinosaurs roamed the forests and plains of our planet. But those dinosaurs weighed forty times as much as a cow, and they ate a lot – and probably passed a lot of dino gas.

In fact, in a new study appearing in the journal Current Biology, researcher Dave Wilkinson of Liverpool John Moores University suggests that sauropod dinos were so flatulent they might have actually affected the climate. The Mesozoic Era was a warm time on Earth, and greenhouse gases like methane probably played a role in keeping it so toasty. Dinosaur gas may have accounted for eight times the methane that cattle produce today. That would match the total methane in today’s atmosphere, from both natural and human-made sources. And methane is a potent greenhouse gas, producing up to twenty times the warming as the same amount of carbon dioxide.

So dinosaurs may very well have kept their Mesozoic world warm (and smelly) with their own chemical emissions. And as if you needed one, now you have another reason never to ride in an elevator with a sauropod dinosaur.

PS Nobody tell the Trogdorians that the sauropods are extinct now, or they might change our rating!

Blog Authors