Astronomy news

Empty Space

The way physicists represent the universe and its history are described in Einstein's equation of general relativity, Newton's universal gravitation, and quantum mechanics. The consensus at present supports Big Bang followed by expansion. According to Andre Maeder dark matter and dark energy are only required to make it all fit together because they ignore empty space. He argues empty space and its properties do not change following a dilation or a contraction.

Sand not water

At www.jpl.nasa.gov/news/news.php ... and https://phys.org/print430401551.html ... Martian streaks, dark lines on Mars thought to be evidence of sub-surface flowing water are now thought to be where grains of sand and dust slip downhill to make streaks rather than seeping water. The Mars Renaissance Rover camera has been studying them and found they only occur on steep slopes ...

   ... they behave like sand grains tumbling on sand dunes on Earth.

Oumuamua

At http://spaceweather.com (November 20th) we have news of another round of solar wind making a rendevous with the Earth in the next few days, coinciding with a mild November here in the UK. We also have an image of an 'interstellar asteroid' first seen by the Pan-STARRS telescope weeks ago when it was thought to be an interstellar comet. It is now classified as an asteroid as it has failed to bring on a cometary show as it approached the Sun. It is passing through the solar system ...

Ceres

The DAWN mission is still throwing up info - see https://phys.org/print429466672.html ... a study in Geophysical Research Letters analysed surface features on Ceres in order to find clues about the interior of the asteroid. Chains of pits and small craters and other features litter the surface. Upwelling from below is thought to have created them. See the image below ...

Neutron Star Collision

Worlds in Collision becomes ever more popular with astrophysicists and astronomers and is basic to the gravitational wave theory currently getting a lot of attention - colliding neutron stars and merging black holes. Apparently, a nearby neutron star collision could cause calamity on Earth - but think of all that gold and platinum it would produce. Even merging black holes would be a disaster, if they occurred too close to our galaxy - and that old bugbear, a supernova event would also be deadly. How near is near?

One Step Closer

Again, this is astrophysics rather than astronomy but never mind, its the universe. The claim is that scientists are one step closer to defining dark matter - go to https://phys.org/print428759704.html ... where  we are told the search is on for dark matter - where it is and what it might be. Dark matter, we are led to believe, makes up to 85 per cent of all matter in the universe. We are apparently another step closer to discovering how to detect dark matter and to define it more accurately. What kind of particles are involved?

Speed of Gravity

At https://phys.org/print428727744.html ... Gravitational waves have allowed astrophysicists to confirm with greater precision what Einstein predicted in his Theory of General Relativity - that gravity does not act instantaneously as Newton thought but propagates at the speed of light. Is this circular reasoning.

Jupiter's Aurorae

Also sent in by Robert - www.dailymail.co.uk/sciencetech/article-5032129/The-mystery-of-Jupiter-s... ... Jupiter's intense southern and northern aurora pulses independently of each other according to UCL led research using NASAs Chandra X-ray observatory and EPAs XMM-Newton observatory. Again, this is published in Nature Astronomy. The research found X-ray emissions pulsing every 11 minutes at the South Pole whilst those at the North Pole were said to be erratic.

Water and Mars

At www.sciencedaily.com/releases/2017/10/171027085747.htm ... scientists still explain land features on Mars by water flow. Experiments seem to show that because of Mars thin atmosphere during warm temperature periods water on the surface may actually boil - which is then able to move large amounts of sand and sediments. This idea has been dreamed up because the geology of Mars is done by Earth geologists where water is thought to shape landscapes and be able to move sediments around.

Saturn's Radiation Belts

The radiation belts of Saturn and the Earth are both affected by the solar wind. Belts of energetic particles move around the planets at high velocities - captured by the respective magnetic fields. On Earth the solar wind controls the intensity of the radiation belt - directly and indirectly. On Saturn it differs. The moons of Saturn play a role.