Astronomers Measure the Background Brightness of the Night sky Across the World. Canary Islands are the Darkest in the Survey

Being able to look up at a clear, dark sky is becoming more and more rare in the rich world.  Authors, artists, and even scientists have started to express concern about what our lack of daily exposure to a dark night time sky might mean for our psyche and our sense of place in the universe.  Now a team has collected photometric data at 44 sites around the world in an attempt to quantify how dark the night sky actually is at different places on the globe. So where was the darkest place surveyed?  The Canary Islands.

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Massive Stars Mix Hydrogen in Their Cores, Causing Them to Pulse Every few Hours or Days

Main sequence stars fuse hydrogen in their cores. It’s how they produce the energy they need to shine and keeps them from collapsing under their own weight. As hydrogen is fused into helium, there is less hydrogen available in the core. This can pose a challenge for large stars. They need to fuse a tremendous amount of hydrogen to keep shining, and they can’t do that when core hydrogen is depleted. Fortunately, they can solve this problem by mixing more hydrogen into their core. A new study in Nature Astronomy shows us how this mixing happens.

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Concerns About James Webb’s Ariane 5 Rocket Might Push the Launch Back

A new report from the US Government Accountability Office (GAO) says that the launch of the long-awaited, highly anticipated James Webb Space Telescope (JWST) will very likely be delayed due to an anomaly identified in the Ariane 5 launch vehicle.  Launch for JWST is currently scheduled for October 31, 2021, but that date could slip by at least a couple of weeks.  

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Webb Fully Unfurls for the Last Time on Earth. The Next Time Will Be in Space

The primary mirror of the long-awaited James Webb Space Telescope (JWST) was opened for the last time on Earth before the launch of the observatory, currently scheduled for October 31, 2021.

During some of the final checkouts before the telescope heads to space, engineers commanded the 18 hexagonal mirrors to fully expand and lock into place, just like they will do once the Webb telescope reaches its destination in space.  

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Extrasolar Object Interceptor Would be Able to Chase Down the Next Oumuamua or Borisov and Actually Return a Sample

What if we had the ability to chase down interstellar objects passing through our Solar System, like Oumuamua or Comet Borisov? Such a spacecraft would need to be ready to go at a moment’s notice, with the capacity to increase speed and change direction quickly.

That’s the idea behind a new mission concept called the Extrasolar Object Interceptor and Sample Return spacecraft. It has received exploratory funding from NASA through its Innovative Advanced Concepts (NIAC) program.

“Bringing back samples from these objects could fundamentally change our view of the universe and our place in it,” says Christopher Morrison, an engineer from the Ultra Safe Nuclear Corporation-Tech (USNC-Tech) who submitted the proposal to NIAC.            

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Gaia Might Even be Able to Detect the Gravitational Wave Background of the Universe

Embry-Riddle researchers used data captured by the Gaia satellite (shown here in an artist’s impression) to determine the ages of stars. Credit: European Space Agency – D. Ducros, 2013

The Gaia spacecraft is an impressive feat of engineering. Its primary mission is to map the position and motion of more than a billion stars in our galaxy, creating the most comprehensive map of the Milky Way thus far. Gaia collects such a large amount of precision data that it can make discoveries well beyond its main mission. For example, by looking at the spectra of stars, astronomers can measure the mass of individual stars to within 25% accuracy. From the motion of stars, astronomers can measure the distribution of dark matter in the Milky Way. Gaia can also discover exoplanets when they pass in front of a star. But one of the more surprising uses is that Gaia could help us detect cosmic gravitational waves.

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