Dancing black holes

Using the supersharp radio “vision” of the National Science Foundation’s VLBA, astronomers have made the first detection of orbital motion in a pair of supermassive black holes in a galaxy some 750 million light-years from Earth.

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The end of an era

The end of a space mission never comes easy. After spending the past eight months attempting to make contact, NASA has formally announced the end of the Opportunity mission on Wednesday, February 13th. The team made last contact with the rover on June 10, 2018, prior to a planet-wide dust storm leading up to opposition last July.

Here is the light curve since 2010 for R Leonis.

Here is the light curve since 2010 for R Leonis.

This Mira type variable has an average period of approx 310 days, so maxima occur nearly two months earlier each year.
With R Leo being located close to the ecliptic, there is a gap in the light curve each summer when Leo is in conjunction with the Sun.
By the British variable stars section.

Martian winds are very active on a local scale

Swirling columns of wind and dust known as dust devils occur frequently, and their tracks crisscross large areas. The largest ones can reach heights of 8 kilometers much taller than dust devils on Earth.
Dust devils on Mars form the same way they do in deserts on Earth. You need strong surface heating, so the ground can get hotter than the air above it. Heated less dense air close to the ground rises, punching through the layer of cooler denser air above rising plumes of hot air and falling plumes of cool air begin circulating vertically in convection cells. Now, if a horizontal gust of wind blows through, it turns the convection cells on their sides, so they begin spinning horizontally, forming vertical columns and starting a dust devil.
A better understanding of how dust devils transport particles into the air, as well as how those particles impact climate and conditions over distances, will improve our understanding not only of weather here on Earth, but also on Mars, aiding in better designs and mission plans for future missions.

Phedias Hadjicharalambous.
Cyprus Astronomy Organisation

NASA’s Mars rover Opportunity recorded this image of a swirling Martian dust devil on March 31 2016.

Asteroid impacts on the Earth and moon have increased since the dinosaurs lived.

Some 290 million years ago, as the last trilobites scuttled across the seafloor, the skies above grew just a little more ominous. At that point, large asteroids including the impactor that would later kill off the dinosaurs began to rain down on our planet between two and three times more frequently than they did before.That impact was singularly catastrophic. But, according to a new study published today in the journal Science, that smashup was also just one episode in an ongoing spike of gargantuan asteroid impacts bombarding our neck of the solar system.

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