Quantcast
Connect with us

Why the idea of alien life now seems inevitable and possibly imminent

Published

on

This article is an edited extract from an essay, The search for ET, in The New Disruptors, the 64th edition of Griffith Review.

We’re publishing it as part of our occasional series Zoom Out, where authors explore key ideas in science and technology in the broader context of society and humanity.


Extraterrestrial life, that familiar science-fiction trope, that kitschy fantasy, that CGI nightmare, has become a matter of serious discussion, a “risk factor”, a “scenario”.

ADVERTISEMENT

How has ET gone from sci-fi fairytale to a serious scientific endeavour modelled by macroeconomists, funded by fiscal conservatives and discussed by theologians?

Because, following a string of remarkable discoveries over the past two decades, the idea of alien life is not as far-fetched as it used to seem.

Discovery now seems inevitable and possibly imminent.

It’s just chemistry

While life is a special kind of complex chemistry, the elements involved are nothing special: carbon, hydrogen, oxygen and so on are among the most abundant elements in the universe. Complex organic chemistry is surprisingly common.

Amino acids, just like those that make up every protein in our bodies, have been found in the tails of comets. There are other organic compounds in Martian soil.

ADVERTISEMENT

And 6,500 light years away a giant cloud of space alcohol floats among the stars.

Habitable planets seem to be common too. The first planet beyond our Solar System was discovered in 1995. Since then astronomers have catalogued thousands.

Based on this catalogue, astronomers from the University of California, Berkeley worked out there could be as many as 40 billion Earth-sized exoplanets in the so-called “habitable zone” around their star, where temperatures are mild enough for liquid water to exist on the surface.

ADVERTISEMENT

There’s even a potentially Earth-like world orbiting our nearest neighbouring star, Proxima Centauri. At just four light years away, that system might be close enough for us to reach using current technology. With the Breakthrough Starshot project launched by Stephen Hawking in 2016, plans for this are already afoot.

Life is robust

It seems inevitable other life is out there, especially considering that life appeared on Earth so soon after the planet was formed.

ADVERTISEMENT

The oldest fossils ever found here are 3.5 billion years old, while clues in our DNA suggest life could have started as far back as 4 billion years ago, just when giant asteroids stopped crashing into the surface.

Our planet was inhabited as soon as it was habitable – and the definition of “habitable” has proven to be a rather flexible concept too.

Life survives in all manner of environments that seem hellish to us:

ADVERTISEMENT

Tantalisingly, some of these conditions seem to be duplicated elsewhere in the Solar System.

Snippets of promise

Mars was once warm and wet, and was probably a fertile ground for life before the Earth.

Today, Mars still has liquid water underground. One gas strongly associated with life on Earth, methane, has already been found in the Martian atmosphere, and at levels that mysteriously rise and fall with the seasons. (However, the methane result is under debate, with one Mars orbiter recently confirming the methane detection and another detecting nothing.)

Martian bugs might turn up as soon as 2021 when the ExoMars rover Rosalind Franklin will hunt for them with a two-metre drill.

ADVERTISEMENT

Besides Earth and Mars, at least two other places in our Solar System might be inhabited. Jupiter’s moon Europa and Saturn’s moon Enceladus are both frozen ice worlds, but the gravity of their colossal planets is enough to churn up their insides, melting water to create vast subglacial seas.

In 2017, specialists in sea ice from the University of Tasmania concluded that some Antarctic microbes could feasibly survive on these worlds. Both Europa and Enceladus have undersea hydrothermal vents, just like those on Earth where life may have originated.

When a NASA probe tasted the material geysered into space out of Enceladus last June it found large organic molecules. Possibly there was something living among the spray; the probe just didn’t have the right tools to detect it.

Russian billionaire Yuri Milner has been so enthused by this prospect, he wants to help fund a return mission.

ADVERTISEMENT

A second genesis?

A discovery, if it came, could turn the world of biology upside down.

All life on Earth is related, descended ultimately from the first living cell to emerge some 4 billion years ago.

Bacteria, fungus, cacti and cockroaches are all our cousins and we all share the same basic molecular machinery: DNA that makes RNA, and RNA that makes protein.

A second sample of life, though, might represent a “second genesis” – totally unrelated to us. Perhaps it would use a different coding system in its DNA. Or it might not have DNA at all, but some other method of passing on genetic information.

By studying a second example of life, we could begin to figure out which parts of the machinery of life are universal, and which are just the particular accidents of our primordial soup.

ADVERTISEMENT

Perhaps amino acids are always used as essential building blocks, perhaps not.

We might even be able to work out some universal laws of biology, the same way we have for physics – not to mention new angles on the question of the origin of life itself.

A second independent “tree of life” would mean that the rapid appearance of life on Earth was no fluke; life must abound in the universe.

It would greatly increase the chances that, somewhere among those billions of habitable planets in our galaxy, there could be something we could talk to.

ADVERTISEMENT

Perhaps life is infectious

If, on the other hand, the discovered microbes were indeed related to us that would be a bombshell of a different kind: it would mean life is infectious.

When a large meteorite hits a planet, the impact can splash pulverised rock right out into space, and this rock can then fall onto other planets as meteorites.

Life from Earth has probably already been taken to other planets – perhaps even to the moons of Saturn and Jupiter. Microbes might well survive the trip.

In 1969, Apollo 12 astronauts retrieved an old probe that had sat on the Moon for three years in extreme cold and vacuum – there were viable bacteria still inside.

ADVERTISEMENT

As Mars was probably habitable before Earth, it’s possible life originated there before hitchhiking on a space rock to here. Perhaps we’re all Martians.

Even if we never find other life in our Solar System, we might still detect it on any one of thousands of known exoplanets.

It is already possible to look at starlight filtered through an exoplanet and tell something about the composition of its atmosphere; an abundance of oxygen could be a telltale sign of life.

A testable hypothesis

The James Webb Space Telescope, planned for a 2021 launch, will be able to take these measurements for some of the Earth-like worlds already discovered.

ADVERTISEMENT

Just a few years later will come space-based telescopes that will take pictures of these planets directly.

Using a trick a bit like the sun visor in your car, planet-snapping telescopes will be paired with giant parasols called starshades that will fly in tandem 50,000 kilometres away in just the right spot to block the blinding light of the star, allowing the faint speck of a planet to be captured.

The colour and the variability of that point of light could tell us the length of the planet’s day, whether it has seasons, whether it has clouds, whether it has oceans, possibly even the colour of its plants.

The ancient question “Are we alone?” has graduated from being a philosophical musing to a testable hypothesis. We should be prepared for an answer.The Conversation

Cathal D. O’Connell, Researcher and Centre Manager, BioFab3D (St Vincent’s Hospital), University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.


Report typos and corrections to: [email protected].
READ COMMENTS - JOIN THE DISCUSSION
Continue Reading

Breaking Banner

Desperate Trump looking for a Dem senator to vote to acquit him in effort to soften blow of impeachment

Published

on

According to a report from the Washington Post, President Donald Trump is hoping to find at least one Democrat who will vote to acquit him as Senate majority Leader Mitch McConnell (R-KY) attempts to wrap the president's impeachment trial up as quickly as possible.

The report notes that the President has targetted Sen. Joe Manchin (R-WV) as a likely candidate and the White House focus behind the scenes is the hope they can count on his one vote that would give the anticipated acquittal a partisan sheen.

Continue Reading

Facebook

California confirms third case of China virus in US

Published

on

A patient in California's Orange County was Saturday confirmed as the third person on US soil infected with the new deadly virus that originated in China, health officials said.

The infected person was a traveler from Wuhan, the Chinese city at the epicenter of the outbreak, the Orange County Health Care Agency said.

The Centers for Disease Control and Prevention (CDC) confirmed the patient had tested positive for the Novel Coronavirus, it said.

The individual was in isolation in a local hospital and was in good condition.

"There is no evidence that person-to-person transmission has occurred in Orange County. The current risk of local transmission remains low," the health care agency said.

Continue Reading
 

Facebook

Japan will evacuate nationals from China virus city: Prime Minister Abe

Published

on

Japan will evacuate all its nationals from China's quarantined city of Wuhan, the epicentre of a deadly virus, Prime Minister Shinzo Abe said Sunday.

"We have decided to send back all (Japanese citizens in Wuhan) to Japan if they wish so, by every means including a chartered flight," Abe told reporters.

"We are coordinating with the Chinese government at various levels, and we will accelerate the process to realise a swift implementation" of the evacuation from Wuhan, the capital of Hubei province in central China, Abe said.

Earlier, a foreign ministry official told AFP that 430 Japanese were in Hubei province.

Continue Reading
 
 
Help Raw Story Uncover Injustice. Join Raw Story Investigates for $1 and go ad-free.
close-image