Gravity Speed of Light

Jovan has sent in a lot of links this week. Here are two of them. At http://blogs.discovermagazine.com/d-brief/2017/12/08/speed-of-gravity-li... .... why does gravity travel at the speed of light. This idea is derived from the recent gravitational waves generated from a collision of two stars, 130 million years of age - in a far away galaxy. They reached the Earth in August 2017. These were neutron stars and the collision caused a gravitational wave - but gravity appears to have traveled at the same speed as light emitted from the same collision.

Fault on Mars

Robert sent in a number of links on the same subject - geology on Mars. More specifically, a so called fault line. See for example www.dailymail.co.uk/sciencetech/article-5177241/Glitches-matrix-NASA-rev... ... NASA reveals a stunning image from Mars. Robert asks, but is it all what it seems, a fault line.

Australia Shelf

At https://phys.org/print432201867.html ... the Southern Surveyor research vessal has been looking at the continental shelf system off New South Wales and they have discovered huge underwater landslides close to the shore. They date back hundreds of thousands of years ago (not sure how they arrived at the dates) but presumably earthquake activity was to blame.

    

Why iron meteorites make landfall but chondrites explode

Why iron meteorites reach the surface of the Earth but chondrites and conglomerate meteors tend to explode in the atmosphere - breaking into many pieces and leaving small scatters on the surface. It's all to do with air penetrating cavities in rocky meteorites causing them to weaken and explode apart. In other words, our atmosphere naturally protects the surface from the hazard of real meteorites - but there are always exceptions to the rule. Large chondrites have the ability to penetrate much closer to the surface - or even reach the surface.

Daffy Duck

Robert sent in the link https://crev.info/2017/12/is-this-duck-a-dinosaur/ ... a dinosaur that looks like a duck ...

Red Spot

Jovan sent in the links below - www.missionjuno.swri.edu/news/juno-probes-depths-of-great-red-spot ... and www.space.com/39066-jupiter-great-red-spot-depth-juno-spacecraft.html ... data collected by NASAs Juno spacecraft indicates that the great red spot penetrates deep below the upper atmosphere of Jupiter. The red spot is a giant oval of crimson coloured clouds that race counter clockwise around the perimeter of the anomaly ....

Hummadruz

The hum has been a subject in Northern Earth magazine for several years - see for example page 25 issue 151, December 2017. At https://phys.org/print431859742.html ... it seems earthquakes can cause the Earth to vibrate for an extended time but in 1998 researchers found the Earth itself generates a low frequency vibrational signal even in the absence of earthquake activity. This has now been extended to the sea floor. Seismometers on land and under the sea have determined the ocean bottom naturally vibrates - a low hum like a wind turbine.

Earth and Venus

Jovan sent in this link - www.skyandtelescope.com/astronomy-news/why-is-earth-magnetized-and-venus... ... why is Earth magnetised but Venus is not magnetised. It seems planetary scientists don't really know what to make of Venus, an admission in a popular magazine available for sale in newsagents. It is in many ways similar to the Earth in matters os size, mass, and rocky composition - but worlds apart in other ways. In atmosphere for example. Venus is cl;oud rich and dense. Surface temperatures are around 460 degrees celsius.

Loch Ness Monster

At https://phys.org/print431945566.html ... geomythology is back in the news. It is still an embryonic science we are told - and has to overcome prejudice and incredulity. It begins with a view over Mount Mazuna, a volcano in Oregon. Native Americans folk tales of its eruption go back 7000 years. Geologists Luigi Piccardi has suggested the Loch Ness monster has something to do with the unusual agitation of the lake's surface water during an earthquake.

Mid Continent Rift

At https://phys.org/print431943147.html ... geologists disprove theory about what stopped the formation of the Mid Continent Rift (in N America). This rift is generally thought responsible for the dramatic cliffs running along the shore of Lake Superior (where ice melt has scoured away sedimentary layers that once covered it ...