NASA : The 2017 Total Solar Eclipse
https://www.youtube.com/watch?v=2VaTYQvB6so


Multimedia | NOAA NESDIS
https://www.nesdis.noaa.gov/content/multimedia

Follow the Moon's Shadow across the Northern Hemisphere
https://www.youtube.com/watch?time_continue=1&v=uZMvd-WZH1A

Can Radio Telescopes Find Axions?
http://aasnova.org/2017/08/16/can-radio-telescopes-find-axions/

In the search for dark matter, the most commonly accepted candidates are invisible, massive particles commonly referred to as WIMPs. But as time
passes and we still haven’t detected WIMPs, alternative scenarios are becoming more and more appealing. Prime among these is the idea of axions.

Axions are a type of particle first proposed in the late 1970s. These theorized particles arose from a new symmetry introduced to solve ongoing
problems with the standard model for particle physics, and they were initially predicted to have more than a keV in mass. For this reason, their
existence was expected to be quickly confirmed by particle-detector experiments — yet no detections were made.

Today, after many unsuccessful searches, experiments and theory tell us that if axions exist, their masses must lie between 10-6–10-3 eV. This is
minuscule — an electron’s mass is around 500,000 eV, and even neutrinos are on the scale of a tenth of an eV!

But enough of anything, even something very low-mass, can weigh a lot. If they are real, then axions were likely created in abundance during the
Big Bang — and unlike heavier particles, they can’t decay into anything lighter, so we would expect them all to still be around today. Our universe
could therefore be filled with invisible axions, potentially providing an explanation for dark matter in the form of many, many tiny particles.

A comparison of Arecibo Observatory radar images of Venus from 1988 and 2012. Via Ed Rivera-Valentín.

The Air out There: Astronomers Aim to Find Atmospheres of Alien Earths - Scientific American
https://www.scientificamerican.com/...out-there-astronomers-aim-to-find-atmospheres-of-alien-earths/

Is our nearest neighboring exoplanet, Proxima b, an "Earth next door," or is it a lifeless rock?

Remotely sniffing the air of these tantalizing worlds is no easy task, and is unlikely to occur sooner than the end of this decade, if not well into the next.
The first observations could be made by NASA’s infrared James Webb Space Telescope, launching in 2018, followed in the mid-2020s by a new generation of ground-
based “Extremely Large Telescopes” with 30-meter mirrors. However, the payoff could be immense: In a forthcoming paper submitted to The Astrophysical Journal,
the Harvard-Smithsonian Center for Astrophysics astronomer Caroline Morley and colleagues conclude that with a total investment of as little as a week of
observing time Webb could conceivably deliver statistically significant detections of Earth-like atmospheric conditions upon a handful of small planets transiting
nearby red dwarf stars. Or, of course, Webb could find instead that those worlds are airless rocks. Whether such investments will happen at all is far from certain:
With a nominal lifetime of only five years and astronomers worldwide clamoring to use it, the telescope is destined to become the most oversubscribed and in-demand
scientific instrument humans have ever built.

In the meantime some researchers are focusing on ways to use Webb to simply detect an atmosphere—or rule one out—upon the closest potentially life-friendly red-dwarf
world. Find that Proxima b has managed to keep an appreciable atmosphere in spite of the barrage of physical insults from its stellar host, and you have taken a big
step toward showing the universe is filled with biologically promising red-dwarf worlds. Finding it has no atmosphere could, by contrast, bolster the case that red
dwarfs are by and large dead-ends in the search for alien life.

“It may sound arrogant, but using Webb to prove that Proxima b has an atmosphere would be one of the biggest scientific achievements it could make,” says Ignas
Snellen, an astronomer at the University of Leiden. “If Webb does that, I think the project would have to be considered a success, no matter what else it does.”