February’s talk

Dr Helen Walker is a familiar face from RAL, and runs the Satellite Operators’ Group. She gave us an update on planetary exploration.

She also gave us an update on the Moon, and that it was time to be a bit more adventurous and explore more exciting areas, rather than the safe, flat maria that we chose for the Apollo missions. The south pole, with its huge Aitken basin (1800km in diameter) has areas accessible with peaks in permanent sunlight and also ice trapped in its craters. There are proposals of creating a base there, such as an igloo-type affair, created out of bricks printed by a 3-D printer and covered by gravel.

Mercury is unlikely to ever be visited by us. Temperatures are too variable. Its surface composition is not as homogenous as that of the Moon, although it looks Moonlike.

Venus may still have active volcanoes as there are hotspots visible in its sky (according to the Venus Xpress orbiter). The Japanese Akatsuki orbiter (which arrived in 2015) is making infra-red observations of its clouds and notes they are very active at night, with a huge wave moving very slowly across the face of Venus as it rotates slowly. She thinks it is caused as the air moves over mountains underneath.

Mars is her first love. The rover Curiosity has now been there for over four years and is in the middle of Gale crater, which was once a lake and has lots of sedimentary rock. There is a crater near the north pole which has a permanent ice rink. One of the Mariner pictures had one white pixel in it. We now know that was the ice lake (and not a duff pixel?!). There are practice runs of a new Mars rover going on in Utah. Mars Utah Rover Field Investigations = MURFI.

Jupiter and its Galilean satellites have plenty going on for us. The Juno craft will be crashed into Jupiter once its mission was over. There are storms and hurricanes going on right to the pole. Does Callisto have rock and ice in an ocean under its surface? Europa’s insides are kept liquid by tidal stresses caused by Jupiter. We are treading very carefully where exploration of Europa is concerned, so we do not cause any possible contamination.

Likewise Saturn’s big moon Titan. Cassini is in its final year of Saturn exploration.

Uranus and Neptune. These two are so far away from us that they looked featureless from telescopes on Earth, but we now have had so many opportunities to see them that we have been able to see Uranus change through the seasons.

Pluto and Charon were passed by the wonderful New Horizons probe in 2015. Pluto’s icy surface is rock hard.

Comet 67p, which was visited so successfully by Rosetta and little Philae, is seen to consist of two different cometary bodies which came together slowly.

In the final stages of her talk she dismissed the possibility of seeing a planect direcitly, such as when Hubble was believed to have seen a very slow moving planet orbiting Fomalhaut. She postulates an icy ring.

Clear skies.

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