More than 3 billion years ago, Mars was a very different place.
It wasn't the rusty, dead seeming world we see today. Instead, lakes, rivers, and deltas likely covered much of the planet's surface. Thanks to previous NASA research, we know that at least some parts of the planet were, in fact, capable of supporting microscopic life as we understand it.
But who knows what once lurked within Martian waters.
Over the years, we've sent robotic missions to Mars to try to figure out the answer to this very question, and on Thursday, NASA announced that its Curiosity rover brought us another step closer toward figuring out if life once existed on the red world.
Two new studies published in the journal Science this week detail findings by Curiosity that hint at possible signs of life in Mars' distant past.
“With these new findings, Mars is telling us to stay the course and keep searching for evidence of life,” Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA, said in a statement.
“I’m confident that our ongoing and planned missions will unlock even more breathtaking discoveries on the Red Planet.”
Organics on Mars, but what about life?
One of the studies details organic compounds found by the rover in preserved rock that dates back about 3 billions years.
Organic compounds are incredibly important when hunting for life elsewhere in the solar system. All life on our planet is carbon-based, so finding organics elsewhere could hint, but not necessarily confirm, the existence of alien life.
While the organics themselves aren't signs of life -- they could have been formed through natural geological processes -- it's possible that the chains of carbon molecules found on Mars by Curiosity's drill were once part of something that was living or even food for a living creature, planetary geologist Kirsten Siebach said in an interview.
"The key point in this paper is that the specific molecules they’ve seen broke off a larger carbon-based molecule," Siebach, who wasn't involved with the new studies but does work with Curiosity, added.
That said, it's not as if Curiosity can trace back the origin of these organics, but at least the long-preserved molecules will give us hope for one day finding signs of life preserved in the rusty Martian dirt.
“Curiosity has not determined the source of the organic molecules,” Jen Eigenbrode, lead author of the organics study, said in the NASA statement.
“Whether it holds a record of ancient life, was food for life, or has existed in the absence of life, organic matter in Martian materials holds chemical clues to planetary conditions and processes.”
Seasonal changes in methane
A second study in Science also details another finding that might have some bearing on whether life exists or has ever existed on Mars.
Over the course of 3 years on Mars -- which equates to about 6 years on Earth due to Mars being further from the sun -- Curiosity kept an eye on how much methane it was able to detect in the planet's thin atmosphere at any given time.
Curiosity detected bursts of methane in the atmosphere at seemingly random times in the past, but the new study shows that the rover actually found a seasonal pattern in releases of methane these days.
"This is the first time we've seen something repeatable in the methane story, so it offers us a handle in understanding it," Chris Webster, lead author of the methane study, said in the statement.
"This is all possible because of Curiosity's longevity. The long duration has allowed us to see the patterns in this seasonal 'breathing.'"
Most of the methane in Earth's atmosphere is actually created by life (cow farts, for example). But that's not necessarily the case with Mars.
It's possible that the methane Curiosity found is actually created through basic geological interactions and is then released later on during seasonal changes in temperature, releasing more in the summer and less in the winter months.
And a note about alien hype
Both of these studies are objectively important, but that said, they were hyped beyond belief.
NASA sent out a pre-announcement stating that it would announce something about Mars about a week before the actually studies were released.
All this serves to do is create a situation in which an important -- but relatively incremental -- story is given a huge amount of attention for days ahead of the actual announcement.
Press coverage before the announcement was speculative at best and downright alien panic-inducing at worst.
And NASA can't feign ignorance that these pre-announcements don't create the hype.
The space agency knows exactly what it's doing when it releases vague announcements of an impending announcement every few weeks. Just look at how it worked out when it pre-announced something about alien life on other planets.
But NASA isn't the only culprit.
News organizations around the world buy into the very system that enables this kind of breathless hyping.
Every week, science journalists around the world agree to adhere to embargoes that ostensibly give us time to report out stories, talk to outside sources, and create a balanced picture of what a new study says.
It makes sense, in theory. This way we're all on the same timetable and have the same resources.
But that's not really how it plays out most of the time. When big studies like these are given spots in prominent journals, it creates a situation in which publications feel the need to cover a new finding, even if it's not that big, just for the sake of competition.
Plus, this kind of hype confuses the public, and at the end of the day, disappoints many folks who only keep track of space on the periphery.
If someone sees an occasional story about how NASA is going to announce some groundbreaking finding related to aliens, they will obviously get excited. However, when they find out what the actual story is? It may not be so exciting.
Fear not, though! There are ways to spot an over-hyped science news story coming. Just remember a few simple embargo times, and remember, if you see an announcement scheduled for one of these times, it's probably related to these journals and therefore, probably not about aliens:
NASA announcing something at 1 p.m. ET on a Wednesday? Yeah, that's the exact time that the journal Nature lifts its embargo each week.
How about 2 p.m. ET on a Thursday? Ah yes, that's when Science lifts its embargo.
You can also always check your friendly neighborhood science reporter's Twitter feed to see just how exasperated we all are when staring at an overhyped announcement from a mile away.
