Aliens and where to find them
Is there life elsewhere?
Photo by Greg Rakozy on Unsplash
In the very real terrestrial world of 3 channel television in the 1970s, I loved watching Star Trek. ‘To boldly go’ at ‘warp speed’ across the galaxies every week with Captain Kirk, Spock, Bones, Scottie and the crew of the Starship Enterprise was wonderful escapism enjoyed by the whole family.
In Florida 3 years ago, having been subjected to packed Disney and Universal theme park days by my teenage children, I insisted on a 2-hour drive to the Kennedy Space Centre later in the week. Their huge car park was nearly empty and we queued for nothing all day apart from a short wait, by Disney standards, for the space shuttle simulator - best ride of the week.
Space and our desire to explore it is a popular subject judging by the numerous big budget sci-fi films produced and the underlying philosophical question that they like to play with, ‘is there life elsewhere’ and what happens to humanity if there is?
Arthur C. Clarke, an English science-fiction writer summed up the human dilemma well, “Two possibilities exist: either we are alone in the universe or we are not. Both are equally terrifying.”
Conspiracy theories abound. Area 51, an infamous, not so secret military facility in the Nevada desert has been harbouring aliens for decades. Only a year ago, the Pentagon released 3 US Navy pilot videos featuring unidentified flying objects. They’d been leaked previously, but now have the stamp of government approval, “the videos do not reveal any sensitive capabilities or systems...”. You can view them on YouTube.
Looking for aliens falls broadly into three camps. The first is space exploration. If an object is close enough, go have a look-see. Nasa’s Perseverance Mars rover, has been boldly wandering around the planet’s Jezero Crater since 18th February, firing laser beams at rocks amongst other things. Secondly you build bigger and better telescopes to look from a distance or thirdly, search for radio waves and other signs of technology. The assumption being that other intelligent life has followed a similar evolution to our own and is making a noise.
Wandering around dead or red planets might seem like an expensive folly, as we are not going to find any intelligent Martians. But astrobiologists are keen to discover whether there is microbial life on Mars or under the ocean of Jupiter’s moon, Europa, or in the liquid hydrocarbon lakes found on Saturn’s moon, Titan. Simple life in our own solar system would confirm that life in the Milky Way and beyond is plentiful. From an intelligent life perspective, it becomes much less likely that we are alone. To help organise our thinking, Frank Drake came up with the Drake equation in 1961, a mathematical formula that calculates the possibility of undiscovered life. The equation still has too many unknowns for there to be a right answer, but the discovery of basic life elsewhere would be a significant addition.
There is also a group of astrobiologists which works on SETI - Search for Extra- terrestrial Intelligence. They are looking for evidence that intelligent beings have used technology to build some sort of transmitter. It was popular during the 1960s and 70s when Russia and America were keen to say ‘hi’ to aliens first in the cold war space race. But no aliens turned up.
This lack of aliens frustrated Enrico Fermi who asked a question which has since been referred to as the Fermi Paradox.
“If aliens are so likely, why have we never seen any?”
The universe contains gazillions of stars and planets. Given that the laws of nature which supported our evolution must also exist everywhere, the night sky should be teeming with alien life. There are lots of theories as to why this isn’t the case. One disturbing thought is that technological civilisations destroy themselves before discovery; perhaps through nuclear weapons or by over-burning fossil fuels. Three astronomers from Pennsylvania State University have analysed the history of alien-hunting and have a different theory which echoes that of Dr. Jill Tarter in 2010. She used the analogy that despite decades of searching, it was equivalent to dipping a drinking glass into Earth’s oceans at random to see if it contained a fish. The astronomers considered 9 variables and ended up swapping the glass for a bath tub. It’s too soon to say that Fermi’s question is a genuine paradox.
Habitable Exoplanets Catalogue (hec)
It was only from 2007 onwards with higher-powered telescopes that exo-planets started to be discovered.
Hec is a catalogue of earth-like worlds which was started in 2011. It’s a list of planets beyond our solar system maintained by Abel Méndez and his colleagues at the University of Puerto Rico, Arecibo.
Qualifying planets must be the correct distance from their parent stars and able to maintain liquid water on their surfaces without freezing or boiling.
‘Teegarden b’ is currently at the top of the list. A planet 12 light years away, the innermost of two, it has roughly the same mass as earth, gets a similar amount of light from its sun and is thought to be rocky.
More than 4,000 exoplanets have been discovered so far. A study in the Astronomical Journal, suggests that 50% of the sun-like stars in the Milky Way are orbited by at least one planet capable of sustaining liquid water, which means 300m potentially habitable worlds.
Another consideration for life is what the planet is made of - ocean, continents, dry land, ice? To discover this requires more sophisticated instrumentation such as the James Webb Space Telescope which is expected to launch into orbit on 31 October this year. It has a light collecting area 6 times larger than the Hubble Space Telescope and means it can hunt for molecules such as oxygen and methane which are associated with biological processes on Earth.
NASA’s web site suggests that one of the tasks of the new telescope is to look at a system of 7 planets orbiting a red dwarf star called TRAPPIST-1. Discovered 3 years ago, there are 7 earth-sized worlds orbiting an ultra-cool star 39 light years away. 3 of the planets are in the habitable zone.
It’s never aliens
Astrophysicists these days always start with the adage that it can’t be evidence of alien life. There have been too many instances where something unusual and unexplained has been put down to aliens, only to be explained later scientifically. Pulsars, one of the more famous ones, turned out to be electromagnetic radiation emanating from the poles of distant stars not radio signals from distant civilisations trying to phone home.
Abraham (Avi) Loeb, a professor of astrophysics at Harvard university is less bothered by this taboo. In late 2017, an unusual object, ‘Oumuamua’ (messenger from afar in Hawaiian) was spotted with a strange trajectory. It was the first object ever seen flying in and back out of our solar system. Most objects end up turning circles around the sun. It was classified as a comet but it didn’t behave like one. Its u-shaped flight path took it past the sun at 196,000 miles per hour without a classic comet tail in tow. There was also no outgassing as it accelerated. Normally, frozen gas on the comet warms-up and evaporates exerting a force. There was no evidence of water, dust or gas emissions. ‘Oumuamua’s flight path was analysed by another team of scientists who published a paper in June 2018. After being propelled around the sun, its path shifted from the path it should have followed if gravity was the only force at work. This visitor was being pushed by something else which lessened in intensity as it moved away from the sun. Loeb concluded that it was a paper-thin metallic disc being pushed like a sail by radiation pressure from the sun. Was it an advanced piece of tech, an alien artefact? Unfortunately, when it was first spotted it was already 20 million miles away and heading off into the distance. With no photographs, astronomers have had to infer information by the way sunlight reflected off the object.
With more bigger and better telescopes planned for earth and space in the next decade and the list of possible life-bearing planets growing, the bath tub in the ocean analogy is about to become a fishing net. Who knows what we might catch?
Earth-folk will universally agree this is a very informative blog - I like 👍