Astrobiology Q&A

Here are just a few of the questions I’ve received from people interested in astrobiology and the search for life beyond the Earth. If you would like to know how to get involved in this sort of science, see How to become an astrobiologist.

[For my popular science book on astrobiology, Life in the Universe: A Beginner’s Guide click here.]
[For The Knowledge: How to Rebuild our World from Scratch click here]


Could there be another Earth-like world with dinosaurs still on it?
– Cody, 18
Well, it depends on what you mean by how dinosaur-like. The best opportunity for life to evolve beyond hardy microorganisms into multicellular, land-dwelling animals we think would be offered by another planet like the Earth. Such a world would have a protective atmosphere, warm oceans of liquid water, continents and plate tectonics, and a climate that has been stable for billions of years. We think there is a good chance of many such planets in our galaxy, and so there may well be alien animals out there. And some of these animals could well share many of the features of dinosaurs – using eyes to sense the world around them, be cold-blooded, wield sharp teeth and claws as predators or self-defense as prey, or lay eggs rather than giving birth to live young like us mammals. So in this sense, you could describe life on this planet as being ‘dinosaur-like’. The frustrating thing, though, is that even if such a world existed in our own galaxy, it would be light-years and light-years away, and so we’d never be able to visit it in yours or my lifetime!


Does Astrogeology exist as a subject?
– George, 16
Yes, ‘astrogeology’ is absolutely a real thing! Although, the field is actually called a slightly different name – ‘planetary science’. Planetary science is all about taking what we know of the geology of rocks on Earth, as well as processes that shape the landscape such as volcanism, glaciation, river erosion, sedimentation, cratering, and so on, and applying this knowledge to other planets and moons in the solar system to try to understand how they have evolved over their history. For example, one of my friends focuses on the ancient signs left behind by water on Mars, and another on the cracks and fissures in the icy face of Europa. We even have pieces of other worlds delivered to the Earth – such as Moon rocks retrieved by the Apollo astronauts, or even bits of Mars brought naturally to us as meteorites – and planetary scientists study these closely to understand the minerals and chemistry inside and so how they formed. If you want to work in this area many universities have degrees in geology, and some offer geology with planetary science. Check on the UCAS system what A-levels you need – physics, chemistry and maths would certainly all be helpful (geology won’t necessarily be required as not all schools offer it). After you graduate you can specialise with a Masters course in planetary science or perhaps step straight to a PhD researching in the field and applying your knowledge to exploring other worlds.


Could aliens use materials from their planet to build a spaceship to Earth? And since aliens are accustomed to their planet’s environment, would they find it difficult to survive in Earth’s atmosphere?
– Taner, 16
Sure, planets and moons are all made from the same basic stuff – the same elements in their rocks, oceans and atmospheres. So if we can mine metals on Earth, you’d be able to do the same on other planets and build technology like radio transmitters or spaceships. As to whether a space-faring alien could survive on Earth without keeping his or her (or whatever sexes aliens have!) spacesuit on, it depends on how similar their planet’s environment is. Virtually all animal and plant life on Earth relies on oxygen in the atmosphere, as aerobic respiration releases lots of energy from food molecules to support our complex cells (whereas many microbes can live without oxygen, and some are even poisoned by it). So there’s good reason to expect that complex alien life would also need oxygen, and so would be sustained by a deep lungful of Earth’s air just like us.


Do you believe that alien sightings, such as the Roswell Incident and the Yeni Kent Compound UFO report, are true or that the people were simply imagining the UFOs? 
– Taner, 16
There have been lots of UFO reports around the world, and although some are clearly hoaxes I also think that lots of the reports are honest and are from people who genuinely believe they saw something strange. I just don’t believe that a few strange sightings are good enough evidence to accept that alien spacecraft are visiting the Earth – although I would of course love to be proved wrong! It always strikes me as curious that UFO sightings are only by a few people at a time, and that something obviously technological has never appeared over any of the world’s cities and been seen by hundreds of thousands of people at the same time, and been captured as good-quality footage on video cameras or camera phones.


Where does your money come from to fund your research?
– Bryony, 16
Generally, money for scientific research in the UK comes from one of the national ‘research councils’ that are funded by the government, and so ultimately most of the research in the UK is paid for by everyone’s taxes. Each research council has a particular focus – engineering, biology, physics and astronomy, and so on. My own research funding comes from the UK Space Agency


What have you found to be the best piece of evidence that points to the possibility that aliens exist?
– Faaz, 11
Astrobiology is a very ‘interdisciplinary’ subject, meaning that it involves knowledge from lots of different sciences. There have been recent advances in three main areas that gives us astrobiogists confidence that there may be life beyond our planet. The first area is a whole category of organisms on Earth known as ‘extremophiles’, living in extremely hostile environments like the freezing cold, or very dry, or acidic. These extremophiles could survive the conditions found on other planets and moons. The second advance has been our exploration of the solar system with robotic probes – we’ve discovered that Mars, or Europa, or Enceladus could offer an environment suitable for hardy organisms (like extremophiles) to survive in. And the third area has been the discovery of planets orbiting other stars in the galaxy, known as exoplanets. We believe that there could be scores of Earth-like planets in our Milky Way galaxy, and so hopefully places with the best possible chance for life to develop.


How likely do you think it is that life exists on other planets?
– Alex, 15
Well clearly as someone who has chosen astrobiology as my research career I think that the chances are good of discovering life beyond the Earth! The more we discover about the incredibly adaptability of life on Earth, and the environments suitable for life on other planets and moons, the more confidence we gain that biology may have emerged on other worlds too.


In your opinion, what is the most likely form that this life will take and why?
– Alex, 15
Microorganisms are by far the most diverse forms of life on Earth, and the extremophiles show us just how adaptable bacteria and archaea are to different extreme environments. Furthermore, for the vast majority of the history of life on Earth, it has been solely microbial, with complex multicellular animals and plants appearing in only the past half-billion years or so. For these reasons, if life does exist beyond the earth it will be mostly microbial.


In your opinion, where are we most likely to find life and why?
– Alex, 15
Within our own solar system, the planet Mars, and the moons Europa and Enceladus, are thought to be the most likely to have provided environmental conditions suitable for the emergence of life. We explore these near-by worlds with our space probes. But in recent years we have also been discovering more and more earth-like planets orbiting other suns in the galaxy. Perhaps our telescopes will discover signs of life on one of these exoplanets before we find evidence of past or present life within our own solar system,


What do you think is the most important research project(s) currently underway, that will help us to further investigate life on other planets?
– Alex, 15
Recently, astrobiology has been making huge progress in three main areas:
(1) Extremophiles – we’re finding life on Earth surviving in incredibly inhospitable (to us!) environments, and understanding these limits to habitability, as well as the survival strategies used by extremophile organisms, teaches us about where life might be possible on other worlds
(2) Exploration – our space probes, such as the orbiters we’ve sent to the Jupiter and Saturn systems or the rovers we’ve landed on Mars, have been telling us enormous amounts about the environmental conditions found on other planets and moons in the solar system, and whether they could ever have supported life
(3) Exoplanets – in recent years we’ve been discovering more and more earth-like planets orbiting other suns in the galaxy. We may find that some of these exhibit signs of life that we can detect from far away with our telescopes – such as the presence of both oxygen and methane in their atmosphere.


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