Astronomy news

dark matter challenge

At https://tallbloke.wordpress.com/2016/09/22/researchers-find-new-natural-... ... we learn that in the late 1970s astronomers Vera Rubin and Albert Bosma independently found that spiral galaxies rotate at a nearly constant speed. The implication was that stars and gases inside a galaxy do not decrease with radius as one might expect from Newton's law of the distribution of 'visible' matter. It remains approximately constant.

electrostatic space

At http://www.io9.gizmodo.com/what-if-dark-matter-were-actually-a-vast-elec... ... Steve Roescraft has self published a paper arguing that electrostatic forces could be preventing galaxies from flying apart. He contradicts mainstream by saying that extreme activity at the centre of galaxies (black hole jets) is is able to propel electrons and negatively charged particles towards the outer regions of those galaxies. This would give the galactic core a net positive electric charge while the outskirts wee negatively charged.

Painting Chiron

At http://earthsky.org/space/pluto-paints-its-largest-moon-red ... Images of Chiron beamed back to earth showed the moon of Pluto was reddish in colour in its northern parts. There was speculation at the time on why this might be and now an explanation has been offered - the red colour was painted by nearby Pluto. The theory is that methane gas escaping from Pluto's atmosphere became trapped by Chiron's gravity.

Comet collapsing

At http://phys.org/print393164363.html ... we learn that comets and meteors rotate and it seems this is one of the reasons why they break up so quickly and yet continue to orbit as a block of smaller objects. The break up is rapid and aided and abetted by the presence of water ice (and other gas ices) in comets, which has been standard theory for some time, due, it is thought, to melt by sunshine (or getting too close to the Sun).

Lakes Mars

At http://phys.org/print393168215.html ... it seems the vestiges of lakes on Mars might not all be confined to a very early period of the solar system - and some may have been more recently than previously thought. In fact, one billion years later than the Mars water world theory. NASAs Mars Reconnaissance Orbiter is said to have recorded valleys that carried water into what look like lake basins - and these lakes and filled and overflowed at different times in the past.

142Nd

At http://phys.org/print393166825.html ... a new study seems to contradict the tenant the composition of the earth should not differ too greatly from primitive chondrite meteorites. The latter are considered to date back to the formation of the solar system - and theoretically were formed contemporarily with the earth. The idea is supported by several neodymium (Nd) isotopes and the  occurrence of them in meteorites and in bulk silicate on the earth.

plasma outburst

  at www.spaceweather.com ... September 12th 2016 - a plasma burst on the Sun captured on camera by MaximilanTeodorescu of Romania. Lovely name - fantastic image.

   and here is an image of aurora (filmed in Norway) that inadvertently captured a bright fireball at the same time.

 

Rosetta organics

At http://phys.org/print392535290.html ... the Rosetta mission's dust analysing instrument has found carbon in a more complex from than expected, according to a paper in Nature (Sept 8th 2016). The dust of comet Churyumov-Gerasimenko has come up trumps it would seem as previously, organic material was found in gases sublimated from the comet (in the coma) but now we have the presence of carbon mixed with other elements such as sodium, magnesium, aluminium, silicon, calcium, and iron. These are held together in large macromolecules compounds.

asteroid fly by small

At www.spaceweather.com (Sept 9th 2016) an asteroid buzzed the earth and then headed towards the moon - passing by just 25,000 miles away. It came closest to the southern polar region and therefore did not intersect the orbits of communications and weather satellites. It was just 50 feet in diameter and would have made a nice fireball if it had penetrated the atmosphere of the earth.  See also http://phys.org/print392536461.html ... where we learn astronomers were not aware of its presence until a couple of days beforehand.

Ceres Volcano

This one is fascinating. Ceres, the dwarf planet currently being visited by the Dawn Mission spacecraft has a volcanic dome rising near what is thought to be an impact crater. Not much is said about the latter but the dome rises 13,000 feet and spreads 11 miles across at the base .... (see http://phys.org/print391960502.html) ...