Creatures in the sky

I

f you have ever spent a summer night by a beaver pond or boggy area, you may have seen brief, greenish-white flickering flames.

If so, you have seen Will-o'-the Wisp. In English folklore, he is a nasty-minded, little elven creature whose hobby is luring ignorant travellers further into the swamp, after which they are never seen again.

In Saskatchewan, these flames are called St Louis Lights. The real explanation is much more prosaic.

The flames are from burning phosphine, a compound of phosphorus and hydrogen, produced by rotting vegetable material. It bubbles to the surface of the water and ignites, producing the flames.

What is especially intriguing is that phosphine has been detected in the atmosphere of Venus, which is probably the least boggy place in the Solar System.

The discovery was first made using the James Clerk Maxwell Telescope, in Hawaii, and confirmed using the Atacama Large Millimetres Array in Chile. Phosphine has a characteristic radio signature that can be detected by Earth-based radio telescopes.

It is very likely the phosphine is not produced on the roasting-hot surface of the planet, but high in the atmosphere, where it is much cooler.

We tend to think of the surfaces of planets as sites for life. Could living creatures be present in atmospheres of planets, like some airborne form of plankton? Is this phosphine telling us there are Venusians?

A few decades ago, science fiction author Arthur C. Clarke wrote a few science fiction stories in which space probes encountered a whole menagerie of living creatures spending their lives in the atmosphere of the giant planet Jupiter. Conditions at the surface — if it has what we would understand as a surface — would be hostile to any sort of life we can think of.

However, high in the atmosphere, the temperatures are more reasonable, there are lots of organic chemicals to eat, and with the vigorous atmospheric circulation, there is plenty of weather. This is important for a long-term, healthy environment.

Clarke's concepts of those Jovian creatures are scientifically feasible: great living gasbags and blimps, living their lives feasting on those organic chemicals

Venus is the second planet out from the Sun, and only just a tiny bit smaller than Earth. For a long time we thought it was the Earth's twin. However, we now know that to be far from the truth.

The temperature on the surface is high enough to melt tin and lead, and the pressure is around ninety times the surface air pressure on our planet. The atmosphere is mostly carbon dioxide, with clouds of sulphuric acid droplets.

However, despite the harsh conditions on the surface, the atmospheric pressure and temperature at about 50 kilometres above the surface of the planet are nearly the same as those on the Earth's surface. There are creatures here in Earth that live in really extreme environments, such as in acidic or almost boiling water.

Similarly tough life forms should be able to handle the conditions in Venus' high atmosphere.

It would be exciting to send a (robot) spacecraft to Venus, maybe to deploy a balloon that would spend years exploring Venus' atmosphere, looking for life. However, for the time being there is a much more prosaic thing that we can do.

We are really excited about the discovery of phosphine on another world because here on Earth it is produced by biological processes.

This could be telling us that there is some sort of life in Venus' atmosphere. In the absence of making a suitable Venus visit any time soon, one way forward is to search for ways in which phosphine can be produced by natural processes not involving living things.

This is maybe one of those science projects where we will try hard to succeed, and secretly hope we fail.

• After dark, Saturn and brilliant Jupiter lie low in the south
• Mars is rising in the east.
• Venus, which is even brighter, rises in the early hours.
• The Moon will reach First Quarter on the 23rd.

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.