Yesterday evening, I attended a physics lecture at UCL. I don’t take Physics, but I have a secret love of physics, and sometimes wish that I had chosen to study it at A Level. The topic was “Alien Evolution”, and it was delivered by Dr Lewis Dartnell of the UCL Centre for Planetary Sciences. The lights dimmed, and being sixth formers, the whole auditorium went “Oooooh…”
There are several hazards of space, one being microgravity. The lack of true gravity would affect one’s muscles, as not using your muscles for just 3 weeks would cause them to waste away, and your heart would become weaker, since it has less need to pump blood around your body. Your skeleton would start dissolving away, and reproduction would be difficult. The last bit was not explained in great detail, but being teenagers, we were able to come up with the reasons why ourselves. Cosmic radiation is another hazard of space. It can cause cancer and cataracts, so there is a possibility that one could go blind. The radiation would also affect our immune and nervous systems. Future humans growing up in space may have no hair or eyebrows, since there would be no sweat running down our faces. We may even give up on legs altogether, and become tubby due to the lack of exercise.
Kepler is a relatively new space telescope, like Hubble, but it never gets to look around the night sky. It’s focussed on one tiny patch in the night sky, but apparently it’s okay, because that patch has loads of stars to look at.
Dr Dartnell then moved on to the requirements of plants. To maximise water conservation, surface area would have to be minimised. Plants would also want to maximise light collection spore dispersal. This would be done by being wide and tall. Most importantly, mechanical stability would have to be ensured, since there’s little point in being a plant if a small gust of wind could blow it over. Our sunlight peaks at a green wavelength, so our sunlight is technically green, not yellow. Plants absorb lots of blue (which has the most energy) and red (there’s an abundance of it) light, while green light (which is neither the most energetic nor the most abundant) light is ignored by plants on Earth, and is reflected instead.
He then talked about the human body plan, and talked about what was universal about our bodies. Our head is ultimately our sense organs and processing centre, and it makes sense to have the sense organs and processing centre close together, in order to have faster reactions. We have limbs for manipulation and locomotion, and our skeleton is also a universal feature. The fact that we have five fingers on each hand and four limbs is a contingency, and it is purely chance that we have these numbers of fingers and limbs. Insects have compound eyes, whereas we have camera eyes, which are high resolution. Animals like the octopus and the squid have cephalopod camera eyes, which are far superior to our own eyes. We would expect aliens, if there are any out there, to have camera eyes, because it makes the most sense. We were told that humans came from fish ancestors. Aquatic life forms are streamlined, and Dr Dartnell hypothesised about alien aquatic life forms. They would use peristalsis propulsion, which is how we swallow and digest.
Dr Dartnell talked about Gliese 581G, which is a planet that orbits a red dwarf star, Gliese 581, and is bigger than Earth. It’s near the middle of the habitable zone of its star, which means that it could potentially host life.
The lecture was one of the best that I’ve attended so far. Although it was speculative, it was based on real science, and it gave me a lot to think about on the way home. And guys, don’t worry. According to Dr Dartnell, if aliens did come to Earth, it’s unlikely that they would want to eat us, since it’s easier to get food from elsewhere in space.
*This was written up from notes I made during the lecture. I’ve missed out quite a bit of the lecture, because I had a coughing fit. I seem to only have loud coughing fits in quiet and public spaces.