Life On A Moon

Talk by Natasha Carr (Member)

Student at Leicester University doing Physics and Space Science going into her final year of her Masters.

Friday 15th July 2022

Natasha started by showing a picture (artists impression) of a real planet which was Kelfir 186f which is an Exo planet this was the first one found, this was earth like orbiting round a sun like star and could there be life on that one.  She went through a brief history of Astrobiology when it only became a thing in the 1980’s, she started with 1953 Russian Astronomer Gavriil Adrianovich Tikhov and said the meaning is the study of distribution and evolution of life in the universe.  She moved on to 1959 when Nasa first started to fund Exobiology studies, then she moved on and spoke about the Seti Project which used radio frequencies to look for any life around our galaxy and further out, then came the Viking that went to mars to look for the remnants of life. Back in 1995 the first exoplanet was found using the Doppler Wobble method which at the time was the method to find exoplanets, then Beagle 2 lander was launched but when it landed all communications failed and she said so we have a dead Beagle on Mars.  The Phoenix lander was the next one that she spoke about as its exobiology experiments discovered snowfall which proved the alkalinity of the soil which indicated with the climate that it was once warmer and wetter. She then spoke about the Curiosity Rover, which is a science lab and it is still there almost 10 years later, and it will sing happy birthday to itself on the day of its 10th birthday. The next one which she spoke about was ESA and starts out its Astrobiology and she explained the main 5 objectives to set out a road map for looking for things to maintain for life, but there is also a lot of earth-based research.  ESA and Roscosmos star a collaboration on ExoMars rover and Perseverance to land on Mars.

She then moved on to looking for life, and explained the Drake equations how possible life is and went through the whole equation explaining what each meant and then she asked for us how long had we been using radios and she said not 100 years, then she moved to the Fermi paradox where is everybody and explaining what this was.  Before moving on to Exoplanets explaining there a lot of methods of detection some of which are more useful than others. Originally it was Doppler Wobbler/radial velocity method she went on to explain about each method of finding the exoplanets. She mentioned that the James Webb telescope was going to be looking at direct imaging method.  Then with some maths she explained more about how they found the star velocity and that by using this method they knew the planet was there and get its minimum mass of the planet.  Then she went onto explain the Transit method which has found load more new exoplanets. This is a really good way to look at planets around a star all you need is a really good telescope to see a faraway star you can see the dip in luminosity, you can get the mass by using the Doppler Wobbler method. The Transit method is a really good way at looking for planets as long as they orbit the star several times in the year.  She the moved on to explain the Transmission spectroscopy which can be used on exoplanets to characterise the atmosphere of the planets it also to make measurements of chemical and the physical properties of the planet’s atmosphere.

We now move a bit closer to us as she looks into our solar system for habitability, they look in a few places she will going through Mars, Europa and Venus they do not look for life itself but signatures of life looking for water, biochemistry and the geology that might be able to support life itself.  She starts with her favourite little moon Europa which has been her research topic for a year now, and she says that Europa is the best place to look for life. The scientists think that it looks almost like Earth as it has an iron core they think and a rocky mantel plus a load of water its 8 times the amount of water that is on earth, this moon is smaller than our moon but she says it is the place we need to go to next. There is strong evidence that Europa’s Ocean is in contact with rock as this sounds a lot like how life started on Earth as there are some sub ocean or hydro thermal vents they think, the Tech observatory in Hawaii was looking very closely at these plumes which contained oxygen which indicates there is atmospheric oxygen and it’s a young surface.  Juno flew past in a low orbit and had a look at Europa and saw quite a big change in the magnetic field of Jupiter,this got them thinking that Europa may also have its own magnetic field.  Then she spoke more are about Mars, which is the place that we need to look at next and she said we see these tiger stripes and the poles flipping like it does on earth.  Then she moved onto Venus bit of a weird one because recently there has been speculation that thermoacidophilic extremophiles may live there basically little organisms that like the heat and acidic conditions which Venus is perfect for. Scientists found phosphine in the atmosphere which is a bio signature but the levels were so low and this research was disputed so much not looking good.

Europa lander is scheduled for 2024 but has we know with James Webb and other missions it probably will not launch 2024 but fingers crossed it might. It will be doing chemical and geological analysis on these samples whilst on the moon there will be a little lab on board.  She worked on the Raman spectroscopy it was meant to go on perseverance but the one that went on it  does not work, but the Raman one is going on the Europa lander.