Space Science and the Search for ET and Extraterrestrial Life

Researchers studying the giant Australian cuttlefish have found that males of the species often successfully resort to the marine equivalent of cross-dressing to father offspring. During the mating season, fertile females are usually jealously guarded by large males, preventing smaller males from getting a look in. So the smaller animals often disguise themselves as females, by changing colour and arranging their tentacles in a more feminine fashion, in order to slip past the male consorts lurking nearby. Whilst this strategy is often very successful at winning them an, albeit brief, audience with the female, no one knew whether they actually succeeded in fathering any young this way. So Roger Hanlon and his colleagues have genetically fingerprinted a number cross dressing males whom they saw initiating successful matings, together with the resulting offspring. They found two out of three of the matings resulted in successful fertilisation showing, that when it comes to sex, deception sometimes pays off !

A toxic chemical used to prevent barnacles from clinging to the bottoms of boats may be causing whales to go deaf and to beach themselves, according to a study by scientists at Yale University. TBT, or tributyl tin, is banned in many countries because it was found to cause genetic mutations in some acquatic animals including sea snails, but it is still widely used elsewhere. Now there is growing evidence that TBT could be causing even greater problems in the oceans by damaging animals' ears. Working on guinea pigs, researchers ahve found that TBT stops the outer hair cells in the ear from working properly, leading to hearing loss, suggesting that the same could happen to marine mammals including dolphins and whales. This would have disastrous consequences for these animals because they rely so heavily on their sonar or echolocation for navigation and hunting.

Volker - NASA has a number of new missions, including going back to the moon and maybe even Mars. If astronauts are sent out for long periods of time, they need something to feed themselves. Therefore, we have done a number of plant experiments on space flights to see how the plants respond to zero gravity. We decided to use roof moss because you can pinpoint individual cells and work out the growth mechanism. This is not possible in higher plants as they have millions of cells to look at.

Chris - What are the results so far?

Volker - After growing the moss in space for 14 days, we opened up the containers and found the moss growing in spirals. This is something we hadn't predicted. Originally we thought that it would grow randomly, just like other plants that have been taken into space. On earth, plants are guided by the force of gravity, which ensures they grow in the right direction. Taking gravity away means that they don't know which way to go. The experiments also show that light is not the most important aspect of making sure plants grow upwards. For example, when seeds send up their first shoots they are in the dark, so they only have gravity to guide them.

Chris - How does moss's spiral growth help you understand how plants grow when gravity is present?

Volker - We think the organelles settle in the cell, allowing the cell to know which way is down. I suppose it's quite like a spirit level. These experiments will also help with us to grow other plants in the future. We started with simple moss and can now do similar experiments with more complicated plants. Eventually, we hope to be able to grow lots of plants in space for hungry astronauts !

Chris - Why are you interested in looking at planetary configurations?

Simon - There is only one planet we know that supports life, and this planet has certain things that are special to it. Firstly, Earth is the right distance away from the sun to have liquid water. Secondly, Earth has a very large moon. The fact it gives us tides might be quite important, but more important is that the moon stabilises the Earth's axis. Without the moon, the planet would flip every so often by twenty or thirty degrees. This can be caused by the gravitational effects of other planets. It wouldn't necessarily kill life off, but it certainly wouldn't be good for it! A flipping Earth could have serious problems, so having a large moon is a very fortunate arrangement.

Our solar system also has a massive comet hoover. As comets fly through the solar system, most are caught by Jupiter's gravitational field and stops them crashing into Earth. The last comet to hit Earth killed the dinosaurs, so without a huge planet like Jupiter nearby, life might not get going.

Chris - How many other solar systems are there?

Simon - Billions! The planets we have found so far are all similar to Jupiter, but hopefully we will find an Earth-like planet soon. Jupiter-like planets are easiest to find because they are big, but we have a suspicion that there must be more planets like Earth. Life is probably very common, but the big question is whether any of it is intelligent.

Chris - Are we far from being able to spot Earth-like planets?

Simon - We are close. At the moment, we can look for a slight eclipse in front of stars similar to the recent transit of Venus. We are building satellites to look for these dips. This means that so far, we have only seen the effect of planets on stars: an indirect way of seeing. Other ideas include looking directly at the light from Earth-like planets by blocking out the light from stars. Once can see light from a planet, we can look at its spectrum. The best possible outcome would be seeing ozone in this spectrum. This would indicate a large amount of oxygen, and for this much oxygen, we need life!

We think that conditions on the early Earth were very bad for life as there was no atmosphere. Mars might have been a better place to live at that time, and so life could have started there but we just don't know. To find out if life really did get going on Mars, we need to go there and have a look.

Anything is possible. There are a number of theories about how we can travel through time but they usually involve going into the future using the theory of relativity. Essentially, this involves going so fast that your body clock slows down. When you stop moving so quickly, everything around you will have aged but you will be only a little bit older. In this way, you are able to travel into the future. Another method that has been suggested is to go to a black hole and go out the other end of it. Stephen Hawking doesn't believe time travel is possible because we would have seen people from the future if it were true. A lot of equations in physics don't work backwards, so going back in time seems unlikely. It would be very difficult.