Humanity has long wondered if life exists elsewhere beyond Earth. With the universe being so mind-numbingly vast, the very idea that our tiny, waterlogged rock should alone harbor life seems so…wasteful.
To sate our curiosity, NASA catalogs exoplanets orbiting Milky Way stars to look for potential cradles of extraterrestrial life, such as Kepler-186f, the first validated Earth-size planet orbiting in its star's habitable zone. And the SETI (Search for Extraterrestrial Intelligence) Institute searches space for clues of alien civilizations by, for example, scanning for the residuals of communication technology like narrow-band radio transmissions.
But is it possible we've set our gaze too far to the horizon? Perhaps the greatest chance we have of finding life beyond Earth isn't orbiting some distant star but can be found in our own solar backyard.
What we look for
When looking for suitable habitats for life, astrobiologists search first and foremost for water. Water is the cornerstone of life on Earth. Life needs solvents to perform biochemical processes, and water's title as the universal solvent means that even the simplest of organisms can use it for their molecular interactions.1
Astrobiologists also look for ways energy may enter a system for metabolic processes. On Earth, this form of energy is typically the Sun; however, recent discoveries have led astrobiologists to search for alternative forms, such as geothermal energy.
Finally, they look for other environmental conditions that make life more or less likely: climate, pressure, temperature, atmospheric makeup, and so on.
We should take this moment to make an important distinction. While our solar system may harbor several havens for life, this life will likely not be the intelligent life that SETI searches for. Any neighborly E.T.s we encounter won't be little grey men or green-skinned vixens so much as a small, microscopic, organisms. Think strange, exotic tardigrades. Well, stranger tardigrades.
Mars
Ever since Percival Lowel mapped the “canals" of Mars, our ruddy neighbor has been the go-to planet for science fiction writers imagining extraterrestrial life — from H.G. Wells's colonizing Martians to Ray Bradbury's mystical natives3. The canals proved a trick of the eye, and the Mars Science Laboratory Mission's Curiosity rover has yet to find signs of civilization, but that doesn't mean Mars is out of the extraterrestrial running.
Scientists have discovered dark, narrow streaks on the landscape most likely caused by flowing water. These streaks showed traces of hydrated salt, like what occurs after salt contacts water before it evaporates.
Given Mars' dry, barren landscape and lack of atmosphere, how water got there remains a mystery, but the phenomenon points to the possibility of liquid water not trapped in the planet's polar ice caps, providing a potential habitat for microbial life. Should water flow under the planet's surface, any life could even be shielded from the sun's radiation.
Adding to the intrigue, scientists think that water once covered roughly 20 percent of the surface before Mars's atmospheric gases were stripped away, and the water evaporated into space. Scientists have also discovered meteorites from Mars that contained the remnants of organic material — suggesting the rusted planet once contained the ingredients for life.
Venus
Like Mars, Venus likely enjoyed Earth-like conditions back in the day. Computer simulations of its early environment suggest the possibility of primordial oceans, moderate temperatures, and a habitable climate.
As David Grinspoon, of the Planetary Science Institute, told New Scientist: “Both planets probably enjoyed warm liquid water oceans in contact with rock and with organic molecules undergoing chemical evolutions in those oceans. As far as we understand at present, those are the requirements for the origin of life."
If early life did form on Venus, most of it probably vanished 715 million years ago, along with those oceans. Today's Venus sports an infernal landscape of volcanic activity, surface temperatures approaching 750 Kelvin, and a thick, noxious atmosphere of carbon dioxide with clouds of sulfuric acid.4,5
But it is that very toxic atmosphere that may have saved Venusian life. According to a paper in the journal Astrobiology, the atmosphere could provide a safe haven for microbial life. Using spectroscopic observations, researchers found “dark patches" in the atmosphere composed of “concentrated sulfuric acid and other unknown light-absorbing particles."
While it is unknown if these patches are organic or not, they do have the same dimension as some Earth bacteria, and researchers think they could be the Venusian equivalent of algae blooms (like those that appear in our lakes and oceans).
The jets of Enceladus, c/o NAS
Enceladus and Europa
Moving away from Earth's rocky neighbors, astrobiologists are also considering the possibility that life may exist on the moons of Saturn and Jupiter.
When the Cassini-Huygens spacecraft flew past Saturn's sixth moon, Enceladus, it discovered hydrogen gas in an erupting plume of water.6 The eruption suggested hydrothermal activity may be taking place beneath Enceladus' icy surface. If so, the moon would offer two important ingredients for life — water and energy for metabolic processes.7
Europa's surface is similarly covered in ice, with long streaks of “brown gunk." But beneath that surface, scientist estimate that there could be twice as much water as on Earth. If this Jovian moon also produced hydrothermal activity within that ocean, it too could be a harbor for life.8 A study using computer models has even suggested that Europa may have hydrogen and oxygen in amounts comparable to Earth, even if the moon is lacking in volcanic activity.
NASA is planning to launch a Europa flyby mission in the early 2020s, and the agency's SUBSEA project will be studying hydrothermal environments in the Lō`ihi seamount, off the coast of Hawaii's Big Island, to learn how life can thrive on Earth in conditions similar to those possible on Enceladus and Europa.
Ceres
Our final candidate is Ceres, a dwarf planet and the largest object orbiting in the asteroid belt between Mars and Jupiter. A spherical clump of rock and ice, Ceres would be an unlikely contender for this list until last year, when NASA's Dawn mission detected organic material on its surface.
Originally, it was thought this organic material covered 6–10 percent of the spectral signature, but a recent analysis of the data suggests the amount of could be as high as 40–50 percent. Since carbon-based compounds are necessary for life, it makes for an exciting discovery that could change how we view objects in the asteroid belt.
With that said, this is a recent discovery and much remains unclear. It is possible the organics weren't created on Ceres but planted there by comets, and even if they are native, organic compounds can come about from non-biological processes.
As Ralph Milliken, a professor at Brown University and one of the study's co-authors said in a press release: “Ceres is clearly a fascinating object, and understanding the story and origin of organics in these spots and elsewhere on Ceres will likely require future missions that can analyze or return samples."
The end of life as we know it
So far, our solar search has focused on the conditions for life as we know it. But what about life as we don't know it?
Bacteria recently discovered in Antarctica can survive off just the hydrogen, carbon monoxide, and carbon dioxide they get from the air. These guys make breatharians look gluttonous by comparison and could lead the way to remove water as a prerequisite in our search for extraterrestrial life.
Additionally, Sara Seager, MIT physics professor, considered that alien life may evolve around different chemical combinations than life on Earth and used computer-generated models to devise a list of those possible combinations.
“The theory ended up being, we should maybe consider all potential molecules that would be in gas form," Seager said. “Why not consider all of them? I just combined them in any way possible, like just taking letters in the alphabet and combining them in all ways."
Could life possibly exist in Titan's methane sea? Or could the seeds of life be floating on some yet undiscovered asteroid? The more we learn about life on Earth, the more we learn about the myriad of paths it has taken to thrive, opening avenues for us to find it in our solar system and beyond.
Sources
1. Water: The molecule of life. NASA website. Retrieved on July 5, from https://www.nasa.gov/vision/universe/solarsystem/Water:_Molecule_of_Life.html.
2. NASA dives deep into the search for life. NASA website. Retrieved on July 3, from https://www.nasa.gov/feature/ames/nasa-dives-deep-into-the-search-for-life.
3. The “canali" and the first Martians. NASA website. Retrieved on July 5, from https://www.nasa.gov/audience/forstudents/postsecondary/features/F_Canali_and_First_Martians.html.
4. Was Venus the first habitable world of our solar System? Michael J. Way, David H. Grinspoon, et al. Geophysical Research Letters. Retrieved on July 5, from https://arxiv.org/ftp/arxiv/papers/1608/1608.00706.pdf
5. Venus entry. NASA science: Solar system exploration. NASA website. Retrieved on July 4, from https://solarsystem.nasa.gov/planets/venus/in-depth/.
6. Hydrothermal vents on Saturn's moon Enceladus may harbour life. Andrew Masterson. Cosmos. Retrieved on July 5, from https://cosmosmagazine.com/space/hydrothermal-vents-on-saturn-s-moon-enceladus-may-harbour-life.
7. NASA dives deep into the search for life. NASA website. Retrieved on July 3, from https://www.nasa.gov/feature/ames/nasa-dives-deep-into-the-search-for-life
8. Europa: Our best shot at finding alien life? Paul Rincon. BBC News. Published on March 24, 2017. Retrieved on July 3, from https://www.bbc.com/news/science-environment-38925601
- Map details dramatic shift from CNN to Fox News over 10-year period
- Does it show the triumph of "fake news" — or, rather, its defeat?
- A closer look at the map's legend allows for more complex analyses
Dramatic and misleading
Image: Reddit / SICResearch
The situation today: CNN pushed back to the edges of the country.
Over the course of no more than a decade, America has radically switched favorites when it comes to cable news networks. As this sequence of maps showing TMAs (Television Market Areas) suggests, CNN is out, Fox News is in.
The maps are certainly dramatic, but also a bit misleading. They nevertheless provide some insight into the state of journalism and the public's attitudes toward the press in the US.
Let's zoom in:
- It's 2008, on the eve of the Obama Era. CNN (blue) dominates the cable news landscape across America. Fox News (red) is an upstart (°1996) with a few regional bastions in the South.
- By 2010, Fox News has broken out of its southern heartland, colonizing markets in the Midwest and the Northwest — and even northern Maine and southern Alaska.
- Two years later, Fox News has lost those two outliers, but has filled up in the middle: it now boasts two large, contiguous blocks in the southeast and northwest, almost touching.
- In 2014, Fox News seems past its prime. The northwestern block has shrunk, the southeastern one has fragmented.
- Energised by Trump's 2016 presidential campaign, Fox News is back with a vengeance. Not only have Maine and Alaska gone from entirely blue to entirely red, so has most of the rest of the U.S. Fox News has plugged the Nebraska Gap: it's no longer possible to walk from coast to coast across CNN territory.
- By 2018, the fortunes from a decade earlier have almost reversed. Fox News rules the roost. CNN clings on to the Pacific Coast, New Mexico, Minnesota and parts of the Northeast — plus a smattering of metropolitan areas in the South and Midwest.
"Frightening map"
Image source: Reddit / SICResearch
This sequence of maps, showing America turning from blue to red, elicited strong reactions on the Reddit forum where it was published last week. For some, the takeover by Fox News illustrates the demise of all that's good and fair about news journalism. Among the comments?
- "The end is near."
- "The idiocracy grows."
- "(It's) like a spreading disease."
- "One of the more frightening maps I've seen."
- "LOL that's what happens when you're fake news!"
- "CNN went down the toilet on quality."
- "A Minecraft YouTuber could beat CNN's numbers."
- "CNN has become more like a high-school production of a news show."
Not a few find fault with both channels, even if not always to the same degree:
- "That anybody considers either of those networks good news sources is troubling."
- "Both leave you understanding less rather than more."
- "This is what happens when you spout bullsh-- for two years straight. People find an alternative — even if it's just different bullsh--."
- "CNN is sh-- but it's nowhere close to the outright bullsh-- and baseless propaganda Fox News spews."
"Old people learning to Google"
Image: Google Trends
CNN vs. Fox News search terms (200!-2018)
But what do the maps actually show? Created by SICResearch, they do show a huge evolution, but not of both cable news networks' audience size (i.e. Nielsen ratings). The dramatic shift is one in Google search trends. In other words, it shows how often people type in "CNN" or "Fox News" when surfing the web. And that does not necessarily reflect the relative popularity of both networks. As some commenters suggest:
- "I can't remember the last time that I've searched for a news channel on Google. Is it really that difficult for people to type 'cnn.com'?"
- "More than anything else, these maps show smart phone proliferation (among older people) more than anything else."
- "This is a map of how old people and rural areas have learned to use Google in the last decade."
- "This is basically a map of people who don't understand how the internet works, and it's no surprise that it leans conservative."
A visual image as strong as this map sequence looks designed to elicit a vehement response — and its lack of context offers viewers little new information to challenge their preconceptions. Like the news itself, cartography pretends to be objective, but always has an agenda of its own, even if just by the selection of its topics.
The trick is not to despair of maps (or news) but to get a good sense of the parameters that are in play. And, as is often the case (with both maps and news), what's left out is at least as significant as what's actually shown.
One important point: while Fox News is the sole major purveyor of news and opinion with a conservative/right-wing slant, CNN has more competition in the center/left part of the spectrum, notably from MSNBC.
Another: the average age of cable news viewers — whether they watch CNN or Fox News — is in the mid-60s. As a result of a shift in generational habits, TV viewing is down across the board. Younger people are more comfortable with a "cafeteria" approach to their news menu, selecting alternative and online sources for their information.
It should also be noted, however, that Fox News, according to Harvard's Nieman Lab, dominates Facebook when it comes to engagement among news outlets.
CNN, Fox and MSNBC
Image: Google Trends
CNN vs. Fox (without the 'News'; may include searches for actual foxes). See MSNBC (in yellow) for comparison
For the record, here are the Nielsen ratings for average daily viewer total for the three main cable news networks, for 2018 (compared to 2017):
- Fox News: 1,425,000 (-5%)
- MSNBC: 994,000 (+12%)
- CNN: 706,000 (-9%)
And according to this recent overview, the top 50 of the most popular websites in the U.S. includes cnn.com in 28th place, and foxnews.com in... 27th place.
The top 5, in descending order, consists of google.com, youtube.com, facebook.com, amazon.com and yahoo.com — the latter being the highest-placed website in the News and Media category.
//This will actually fire event. Should be called after consent was verifed