The press have carried a number of stories over recent weeks about the discovery of planets outside of our solar system. But what is the reality behind these "new earths"? Are we about to "boldly go where no one has gone before" or is it a bit more complicated than that?
In recent years the development of new technologies; "the new astronomy", radio telescopes, earth orbiting telescopes, Mars probes, missions to Jupiter, Saturn and huge developments in computer power have produced a vast array of new information about the heavens.
While as yet no one has managed to actually locate heaven, God, Mr Spock, Darth Vader or any other celestial super beings, the night sky is now a lot more densely populated than it was even 20 years ago, or so it seems.
Within our own Milky Way for example scientists have managed to identify a whole series of dwarf planets known as "Kuiper Belt" objects that lie outside the orbit of Uranus and Neptune. One outcome of which is that Pluto, previously a planet, has been relegated to dwarf planet status.
In recent years technological advances have allowed the discovery of planets orbiting distant stars. They can’t be directly seen of course, because they are too small and far away. But their presence can be measured by minute variations in the motion of the star they are orbiting.
Sometimes however, both the size and in some instances the speed of rotation of the stars can be identified. This gives a picture of where the planet might lie in relation to the star. The limitations of measurement mean that effectively only the biggest planets can be accurately identified. Many of these are "brown dwarf" objects, huge planets composed of gas, that are just not quite big enough to experience the gravitational pressures required to begin the process of hydrogen fusion, that would ignite the planet and turn it into a star. The closest comparison to this in our Solar system is Jupiter.
One product of these new discoveries recently has been a debate around the theoretical possibility of earth- like planets… that could potentially support some form of life. Indeed one such planet seems to have been identified a mere 40 light years away. That’s 240 trillion miles by the way. The argument is that, within the range of possible environments in these distant solar systems, there is likely to be an area of space that is neither too hot nor too cold, where liquid water could exist. Of course, if liquid water exists then life (as we currently understand it!) could potentially exist.
This is a bit more complex than it might appear on first glance. This "goldilocks" zone as it’s been termed isn’t simply restricted to a "temperate" area. As recent discoveries on earth have demonstrated, life has been proven to exist in some extreme environments. For example organisms have been discovered in lakes deep beneath the Antarctic ice sheets that remain liquid because of the extreme pressures. At the same time, research has taken place into the volcanic activity on the "mid oceanic ridges" that circle the earth. These represent the active boundaries of "Crustal Plates" which are slowly separating apart, spilling out lava and creating new areas of ocean floor. Scientists have discovered a whole range of creatures that can live in the highly toxic superheated water surrounding the "black smokers", vents pumping out nutrient-rich material associated with the volcanic activities. Indeed some of the creatures living there get all their nutrition from inorganic material.
Life can exist in the ocean depths, under enormous atmospheric pressures and, most astonishingly, bacteria have been discovered deep underground living inside rocks. It seems that life can exist under vastly different conditions.
Most alien life forms in popular culture tend to have American accents and be humanoid or reptilian. Many live in advanced cultures with globally planned economies where money has been abolished. However the reality of alien life could be much more mundane. After all, a huge part of the history of life on earth has been dominated by simple life forms, single-celled organisms and bacteria.
Using mass spectroscopy, a technique that can identify chemicals by the wavelengths of the light they absorb, scientists have identified complex hydrocarbon molecules in space, including amino acids, which are essential elements of carbon based life.
With that in mind and the extreme adaptability of life on earth, scientists consider that it’s possible that life could have evolved on Mars, Titan – one of Saturn’s moons – and even at one stage on Venus, which is now, despite its proximity to earth, an inferno with sulphuric acid rain and a highly toxic atmosphere, brought on by greenhouse gases none the less.
The comparison between Venus and the Earth however brings out an extremely important contradiction in the Goldilocks equation! Although Earth and Venus are close together in astronomical terms, in reality the difference in the conditions between them couldn’t be greater.
Chaos theory explains that small differences occurring in dynamically changing systems can bring about huge changes in the eventual outcomes. From a Marxist point of view we can explain that a given phenomenon is subject to a massive number of variable factors, and that all the processes need to be taken into consideration to predict what actually happens. Formal logic isn’t accurate enough to explain and predict complex events.
Within the context of the recent discoveries of planets circulating distant stars, there are a whole number of factors that could influence how earth-like a planet might be. These include for example; the age, size and composition of the star, the age of the solar system and the distance that the planet lies in orbit around the star.
For example, many scientists believe that our sun is a "second generation star". This means that the sun is at least in part made of atoms that were previously inside an older star that blew up in a supernova, a stellar explosion that produces brilliant light.
The reason for suspecting this is the presence in the solar system of heavy elements, which are expelled by a supernova. These elements have been formed by a whole series of fusions with other atoms. The argument is that in young stars hydrogen tends to fuse with hydrogen, creating helium. In older stars elements such as iron and carbon are formed when the supply of hydrogen becomes smaller and the star shines as a result of the fusion of more complex atoms, formed themselves as a result of earlier fusion.
Older stars, particularly large ones can grow and expand and effectively absorb the solar system around them, before blowing up. Not a nice place to be!
The distance the planet lies away from the star influences the amount of light and therefore heat that it receives. This is important from the point of view of allowing water to exist in liquid form; too hot and it evaporates, too cold it freezes. Too little light and processes such as photosynthesis can’t develop, while the mixture of gases in the atmosphere of a planet will be affected by the amount of light and heat it receives.
The age of a particular solar system is also important. Any roving planet hopper who approached earth a few hundred million years ago would have found a very inhospitable place covered in volcanoes and with a very different atmosphere to now. The earth itself has been transformed time and time again over the millennia by the actions of vulcanicity, continental drift, mountain building, erosion and of course the weather.
So even if the conditions were absolutely right, the planet was in exactly the right place, it was potentially nice and sunny and there were the correct conditions to allow for liquid water, you could arrive a few hundred million years before or after the conditions were right for life to be sustained. This would be quite a shame, if you and your ancestors had travelled a few thousand years to get there.
So the reality is that much of the reporting in the bourgeois press is quite sensationalist and misleading. This shouldn’t come as too much of a shock to politically active workers. On the other hand the huge development of technique and technology that allows for the discovery of new planets circling distant stars shows the potential for the future of mankind – provided we boot capitalism into the asteroid belt at the first opportunity.