Finding Alien Life: Where we search, what we know, and the challenges ahead
By : John Whitworth / Updated : May 9th, 2026 23:20
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Finding alien life begins with identifying planets in the Goldilocks Zone, where temperatures allow liquid water. Most of the 3,500+ known exoplanets are gas giants, but a few stars may host Earth-like worlds. Mars may once have supported microbial life, and Jupiter’s moon Europa could hide an ocean beneath its icy surface.
Vast distances and the speed-of-light limit make exploration difficult, which is why discovering life elsewhere remains one of science’s greatest challenges.
Criteria for Habitable Worlds
Finding Aliens is difficult because there are so many stars and not all of them have planets. We'd have to scour each one. We've found more than 3,500 exoplanets, and many are gas giants, unsuitable for human-like beings to exist. A planet needs to orbit the star in a zone called the Goldilocks Zone, which is not too hot or too cold from the star. It's more likely they will find us as we've been sending radio signals out into space since the advent of radio.
If life ever existed on Mars, it doesn't now unless it is microbial. Venus, Earth and Mars are all within the Goldilocks Zone but only Earth has verifiable life on the planet.
There are trillions of stars in our galaxy alone, and probably as many galaxies as there are stars in our galaxy. The distances between the stars are a significant hurdle for us and them to see. The nearest star to our own planet is four light-years away. In other words, it would take four years to travel non-stop at the speed of light. When we get there, we'd probably only be disappointed as there has not been any evidence yet that the star has an orbiting planet.
Planets discovered outside our solar system have been large gas planets that orbit too close to their star for life to exist. Scientists have identified a star that is not too far away and not too cold, just about right to support an Earth-like planet. You must check out the BBC Report on the matter for more details.
The Interstellar Travel Barrier
One of Albert Einstein's theories is that nothing can travel faster than light. This theory will have to be broken for us to get to and back from any other solar system in a reasonable time. If this were not possible, the only other option would be to send a spaceship with infinite fuel, carrying people on a one-way journey to the new world to colonise it.
This would cause many problems. Who would volunteer for such a journey, coupled up on a spaceship for so long? Would we do what the British did in the early part of the 18th/19th century, who sent convicts to Australia, but this time into space? They would need to sustain themselves in terms of food and the human population. One idea would be to put them to sleep until they reach the new world. Once there, would they welcome any alien life forces we discover at the end of the journey?
The Search for Life on Mars
There has been a great deal of speculation as to whether there is or ever has been life on Mars. The current thinking is that if any life exists on Mars now, it's an elementary viral life form. The British Space Community launched Beagle 2 as part of a European mission to explore Mars and determine whether there is any primitive life. Beagle 2 would land on the planet to conduct experiments on its surface and beam the results up to the Mars Explorer. America is sending two rover vehicles to the planets, and the Japanese are sending ones too. The Beagle 2 will land on the planet on 25th December 2003.
The intense interest in Mars is because Earth and Mars are at their closest. A theory has been expressed that Martians live underground. Unfortunately, we will not discover this unless they live near the surface. The Beagle 2 will not bring back any samples. All experiments will be carried out on the red planet.
Another mission to the planet is planned to bring samples back to Earth in a couple of years. A recent news report said NASA had found the fossilised remains of a virus on a rock from Mars. The rock landed in Antarctica and ended up on the planet after being ejected into space as debris from a meteor that struck it.
The viral remains of Mars rocks have since been discounted. It is my view that life once did exist, but not now. Scientists recently said they discovered methane on Earth, a gas more commonly produced by living creatures. This raises the prospect of life on Mars. For millions of years before the dinosaurs, the only life that existed on Earth was viruses. Humans could only evolve once the conditions were right. Mars has not yet gotten to that position and likely never will.
Speculation exists that Earth and Mars had the right environment for life in the early solar system. Life on Earth could survive, but it wasn't successful on Mars. The BBC website has documented stories relating to the meteorites from Mars. To discover more, start reading from this link.
Potential Life in Europa’s Oceans
Not Europeans but Europans. The only other celestial body that people believe could support life in our solar system is the Jupitermoon Europa. Space probes that have flown past have indicated a large area of frozen water on the Moon. Scientists believe that below the surface could be an unfrozen liquid containing life. An exploration satellite to The Moon is not set to blast off for years yet, five, maybe ten years.
