The Universe Has Trillions Of Life-Supporting Planets. Why Haven’t We Met Aliens?

With, as Carl Sagan famously put it, “billions and billions” of stars out there, many of them with planets that would support life, why aren’t we seeing that life the form of visits from aliens?

The Universe Has Trillions Of Life-Supporting Planets. Why Haven’t We Met Aliens?

It’s statistically pretty likely that there are plenty of planets which support life.


In fact, there are between 1 and 4 billion planets pretty much like Earth just in the Milky Way alone – and there are 100 billion galaxies out there, each with 100 to 1000 billion stars. Which means trillions and trillions of habitable planets. Right?

There’s a thing called the “Fermi Paradox” that basically lays out the possible reasons why.

(Yes, the Fermi Paradox came from physicist Enrico Fermi. Part of it — the odds that life exists elsewhere — is closely related to the Drake Equation). The first aspect of the Fermi Paradox is that sheer numbers concept above. The second aspect is that life tends to do well despite adversity, and it tends to colonize new habitats, pretty much all the time.  

So … why haven’t any E.T. types come and said hello? 

Here are a few of many possible reasons:

1) Maybe it’s actually pretty difficult for complex life like that on our planet to develop. We don’t know yet. Maybe we’re unique or one of the first civilizations that’s made it this far. 

2) It’s also possible that there’s a hard stop that means that any planet that supports life eventually stops supporting life and everything dies off — or kills itself. In other words, it’s possible that civilizations on all worlds hit a point where they destroy themselves, or are eliminated naturally. Always. Just as an example, 99% of all species that have ever lived on this planet are gone now.

3) This one’s scary but fascinating. Maybe there’s an ancient civilization that monitors the universe and when all worlds hit a certain point where they’re getting too big for their britches, steps in and takes them out. Bam.

4) There might be some extremely intelligent life forms out there that have checked us out, but decided to stay the heck away because we’re entirely too dangerous. I recall a Kurt Vonnegut sub-story called “The Dancing Fool” within the novel “Breakfast Of Champions” that rather hilariously depicts a version of that. Paraphrased, an alien with the knowledge to end wars and cancer but communicates solely by tap-dancing and farting lands in Connecticut, where he discovers a house on fire. He rushes in, dancing and farting away to warn them of the danger. The head of the house grabs his golf club and pummels the alien in the head until he’s quite dead.

Smart aliens could take one look at us and wisely decide to stay the heck away.

5) Maybe, just maybe, we are indeed alone in the universe. I mean, it seems unlikely that this is the case based on sheer numbers. But still … it’s possible. 

Some other things to consider: 

Time is a big factor — compared to the life of most planets and stars, humans have been here and able to communicate beyond ourselves for just a tiny sliver of time. So if someone happened across our Blue Dot and checked in on what kinds of life forms might be here, it could have been before we were even a species. 

And there’s the additional consideration of distance — a ship would have to travel at thousands of times the speed of light to even cross the great divide that separates our solar system from the rest and arrive before the occupants are nothing but dust.

Maybe most or all life forms just don’t ever make it long enough to figure out how to reach out to other life-sustaining planets. It’s a daunting prospect — if it's even possible — to travel that far, that fast. And even then, they’d have to travel specifically to our postal code in the universe in order to even find us. Unless they knew we were here by picking up our telecommunications or TV broadcasts or energy releases (nuclear bombs, NASA launches, etc.) or whatever other signals we might be casting into space, how would they know to travel here? And that’s even assuming that they’d be able to pick up those flags; they could be operating on a totally different level and wavelength. 

To me, it’s far more likely that we’ll find something hurtling past our planet or solar system that’s a shell of a ship or a remnant of a satellite, long empty of life and maybe much else.

Or perhaps, like our Voyager space craft, someone will send something like a message in a bottle and it will long outlive the civilization which sent it off with a kiss and a wave.

Here’s a short video that gets deeper into the Fermi Paradox:

And for some solutions and ideas related to the Fermi Paradox, here's another video from the same people — their YouTube channel is here, and their Patreon page exists as well.

Thumbnail image creative commons licensed from Pixabay.

A landslide is imminent and so is its tsunami

An open letter predicts that a massive wall of rock is about to plunge into Barry Arm Fjord in Alaska.

Image source: Christian Zimmerman/USGS/Big Think
Surprising Science
  • A remote area visited by tourists and cruises, and home to fishing villages, is about to be visited by a devastating tsunami.
  • A wall of rock exposed by a receding glacier is about crash into the waters below.
  • Glaciers hold such areas together — and when they're gone, bad stuff can be left behind.

The Barry Glacier gives its name to Alaska's Barry Arm Fjord, and a new open letter forecasts trouble ahead.

Thanks to global warming, the glacier has been retreating, so far removing two-thirds of its support for a steep mile-long slope, or scarp, containing perhaps 500 million cubic meters of material. (Think the Hoover Dam times several hundred.) The slope has been moving slowly since 1957, but scientists say it's become an avalanche waiting to happen, maybe within the next year, and likely within 20. When it does come crashing down into the fjord, it could set in motion a frightening tsunami overwhelming the fjord's normally peaceful waters .

"It could happen anytime, but the risk just goes way up as this glacier recedes," says hydrologist Anna Liljedahl of Woods Hole, one of the signatories to the letter.

The Barry Arm Fjord

Camping on the fjord's Black Sand Beach

Image source: Matt Zimmerman

The Barry Arm Fjord is a stretch of water between the Harriman Fjord and the Port Wills Fjord, located at the northwest corner of the well-known Prince William Sound. It's a beautiful area, home to a few hundred people supporting the local fishing industry, and it's also a popular destination for tourists — its Black Sand Beach is one of Alaska's most scenic — and cruise ships.

Not Alaska’s first watery rodeo, but likely the biggest

Image source: whrc.org

There have been at least two similar events in the state's recent history, though not on such a massive scale. On July 9, 1958, an earthquake nearby caused 40 million cubic yards of rock to suddenly slide 2,000 feet down into Lituya Bay, producing a tsunami whose peak waves reportedly reached 1,720 feet in height. By the time the wall of water reached the mouth of the bay, it was still 75 feet high. At Taan Fjord in 2015, a landslide caused a tsunami that crested at 600 feet. Both of these events thankfully occurred in sparsely populated areas, so few fatalities occurred.

The Barry Arm event will be larger than either of these by far.

"This is an enormous slope — the mass that could fail weighs over a billion tonnes," said geologist Dave Petley, speaking to Earther. "The internal structure of that rock mass, which will determine whether it collapses, is very complex. At the moment we don't know enough about it to be able to forecast its future behavior."

Outside of Alaska, on the west coast of Greenland, a landslide-produced tsunami towered 300 feet high, obliterating a fishing village in its path.

What the letter predicts for Barry Arm Fjord

Moving slowly at first...

Image source: whrc.org

"The effects would be especially severe near where the landslide enters the water at the head of Barry Arm. Additionally, areas of shallow water, or low-lying land near the shore, would be in danger even further from the source. A minor failure may not produce significant impacts beyond the inner parts of the fiord, while a complete failure could be destructive throughout Barry Arm, Harriman Fiord, and parts of Port Wells. Our initial results show complex impacts further from the landslide than Barry Arm, with over 30 foot waves in some distant bays, including Whittier."

The discovery of the impeding landslide began with an observation by the sister of geologist Hig Higman of Ground Truth, an organization in Seldovia, Alaska. Artist Valisa Higman was vacationing in the area and sent her brother some photos of worrying fractures she noticed in the slope, taken while she was on a boat cruising the fjord.

Higman confirmed his sister's hunch via available satellite imagery and, digging deeper, found that between 2009 and 2015 the slope had moved 600 feet downhill, leaving a prominent scar.

Ohio State's Chunli Dai unearthed a connection between the movement and the receding of the Barry Glacier. Comparison of the Barry Arm slope with other similar areas, combined with computer modeling of the possible resulting tsunamis, led to the publication of the group's letter.

While the full group of signatories from 14 organizations and institutions has only been working on the situation for a month, the implications were immediately clear. The signers include experts from Ohio State University, the University of Southern California, and the Anchorage and Fairbanks campuses of the University of Alaska.

Once informed of the open letter's contents, the Alaska's Department of Natural Resources immediately released a warning that "an increasingly likely landslide could generate a wave with devastating effects on fishermen and recreationalists."

How do you prepare for something like this?

Image source: whrc.org

The obvious question is what can be done to prepare for the landslide and tsunami? For one thing, there's more to understand about the upcoming event, and the researchers lay out their plan in the letter:

"To inform and refine hazard mitigation efforts, we would like to pursue several lines of investigation: Detect changes in the slope that might forewarn of a landslide, better understand what could trigger a landslide, and refine tsunami model projections. By mapping the landslide and nearby terrain, both above and below sea level, we can more accurately determine the basic physical dimensions of the landslide. This can be paired with GPS and seismic measurements made over time to see how the slope responds to changes in the glacier and to events like rainstorms and earthquakes. Field and satellite data can support near-real time hazard monitoring, while computer models of landslide and tsunami scenarios can help identify specific places that are most at risk."

In the letter, the authors reached out to those living in and visiting the area, asking, "What specific questions are most important to you?" and "What could be done to reduce the danger to people who want to visit or work in Barry Arm?" They also invited locals to let them know about any changes, including even small rock-falls and landslides.

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