Astronomy news

Oxygen and Comets

At https://phys.org/print413432138.html ... why do comets expel oxygen? It was first encountered in early 2015, and previously was unknown (or that is what is implied). It  was revealed in the data received from Comet Churyumov-Gerasimenko via the Rosetta Mission. It was discovered as a component of the comet's atmosphere, or coma. We don't know if oxygen is a component in the atmosphere's of other comets but it may be.  The paper, in Nature Cummunications (May 2017), suggests water vapour molecules stream off a comet as it is heated by the Sun.

Jupiter

At www.newscientist.com/article/2129805-first-results-from-jupiter-probe-sh... ... Gary sent in this link to the New Scientist website - Jupiter probe shows huge magnetism and storms. Big planets come with big surprises, the author of the piece begins - and yes, surprises seem to be in store. The annual meeting of the European Geosciences Union was treated to the first release of data from the Juno spacecraft, now in orbit around Jupiter. It's a game changer. There is a dense zone of ammonia gas around its equator and lots of ammonia clouds elsewhere.

Rings Around ...

In 2014 two rings, separated by a gap, were discovered around Chariklo, the largest known of the Centaur objects orbiting between Jupiter and Neptune. It is hundred of kilometers across and its rings are as opaque as those around Saturn and Uranus. Japanese researchers have modelled the two rings around Chariklo and concluded the inner ring, at least, should be unstable - without help to keep it afloat. The fact the rings are in existence suggests small particles - but another possibility is they remain as a result of a shepherd satellite (a big object amongst the particles).

Orbital Evolution

At https://phys.org/print412490580.html ... an interesting link after Bob Johnson's talk at the SIS Spring Meeting on 29th April. The orbits of the planets are affected by two uniformitarian acceptable processes - one developed by Einstein, and the other, by Newtonian theory of gravity. In the latter an orbit becomes narrower over time, more and more elliptical, moving the object closer to the Sun at it's furthest point. The other concerns the periodic shift of the orbit of Mercury which is part of general relativity.

Screaming Clouds

At www.q-mag.org/meteorologists-explain-the-scream.html (see also https://phys.org/print412243519.html ) ... we have a post on Norwegian painter Edvard Munch, and a new interpretation of what it was he actually painted on his canvas. He has posed a mystery to the art world - and made it worse by what he said at the time (which is quoted at the link). Subsequently, various theories have been aired - what was it all about? He depicted a sky filled with blood like clouds and spoke about it feeling like the whole of nature was screaming.

Sun's magnetic field

At www.dailygalaxy.com/my_weblog/2017/04/new-nasa-discovery-our-sun-and-pla... ... (and see also https://phys.org/print412251784.html ) which informs us that new data from the Cassini mission and beamed back by Voyager spacecraft and NASAs Interstellar Boundary Explorer (IBEX). This indicates the Sun and the solar system are surrounded by a giant 'round' magnetic field. This new discovery calls into question the rpevious view of the solar magnetic field trailing behind the Sun with an elongated, comet like, tail. 

Close Approach Comets

Laurence sent in the link https://science.nasa.gov/news-articles/close-approach-comets/ ... which has a video of the close approach of comets. However, we also learn that in 2017 and 2018 there will be two comets that come fairly close to Earth, one at 30 lunar distances, and the other, a bit further out. One close approach has already passed us by - that of comet 41P. We have 45P later this year and 46P in December of 2018 (otherwise known as Comet Wirtanen).

Orbits

At www.everythingselectric.com/nice/ ... we have a nice piece on nice smooth planetary migrations. We learn that Neptune moved from 20AU to its current location at 30AU in a very slow and calm movement. The heavily populated mean-motion resonances in the Kuiper Belt strongly suggests that the orbits of the planets have migrated. This is the so called Nice Model. It proposes the migration of planets from an initial configuration long after the dissipation of the proto planetary gas disk.

Comet PanSTARRS

At www.spaceweather.com (April 12th 2017) Comet PanSTARRS has become highly active. Last week the comet brightened six fold- now amateur astronomers are photographing an incredible tail (see below) ...12th 2017) Comet PanSTARRS has become highly active. Last week the comet brightened six fold- now amateur astronomers are photographing an incredible tail (see below) ...