The Cosmos Astronaut

Earth｜Space｜Universe

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It’s a crazy world out there

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Perseids Flying in from their Radiant Point! [twitter: @mikeyyy0]

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“Fire in Space” by NASA

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Behold! The Perseid Meteor Shower

In this 30-second exposure, a meteor streaks across the sky during the annual Perseid meteor shower, Wednesday, Aug. 11, 2021, as seen from Spruce Knob, West Virginia.

Learn more about the annual Perseid meteor shower. Find out how you can see them in skies across North America!

Image Credit: NASA/Bill Ingalls

Source: NASA

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The UN Sounds All the Alarms

Photo source: Morning Bew

The Intergovernmental Panel on Climate Change (IPCC), an official UN task force, released a 3,949-page report from 234 scientists yesterday that called current climate change trends a “code red for humanity.”

Here’s what you need to know

It’s all our fault. If there was any doubt that maybe we could partly blame volcanoes for climate change, the IPCC put it to rest. “It is unequivocal that human influence has warmed the atmosphere, ocean, and land,” the scientists wrote. They found that human activity has increased the global average temperature by about 2 degrees Fahrenheit since the Industrial Revolution of the 19th century.

Weather goes mid-2000s candy “EXXTREME!” Tropical storms, heat waves, wildfires, droughts, and flooding are all expected to get more severe and more frequent if climate change continues at its current rate, the report said.

More extreme weather shouldn't just be thought of in the future tense, but the here and now. Just last week Greece, Turkey, and much of the Western US experienced some of their worst wildfires in history. 

All eyes on the energy industry. The report blamed one particular human activity for exacerbating climate change: burning fossil fuels. CO2 levels in the atmosphere are the highest they’ve been in 2 million years. 

“This report must sound a death knell for coal and fossil fuels before they destroy our planet," UN Secretary-general Antonio Guterres said. 

There’s a little hope. Since the IPCC’s last big report in 2013, countries have done a better job in curbing carbon emissions. But they need to speed up those cuts dramatically, the report argued. Otherwise, it will be nearly impossible to keep global temps from spiraling higher.

Looking ahead...world leaders will head to Glasgow, Scotland, in November for the pivotal COP26 international climate talks. They'll be tasked with taking the IPCC's scientific report and turning it into meaningful policy. 

Source: Morning Brew

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Staring at the Sun

On April 29, 2015, NuSTAR, Hinode, and Solar Dynamics Observatory all stared at our Sun.

Flaring, active regions of our Sun are highlighted in this image combining observations from  Nuclear Spectroscopic Telescope Array, or NuSTAR (shown in blue); low-energy X-rays from Japan's Hinode spacecraft are green; and extreme ultraviolet light from Solar Dynamics Observatory, or SDO, are yellow and red. This NuSTAR image is a mosaic made from combining smaller images.

The active regions across the Sun’s surface contain material heated to several millions of degrees. The blue-white areas showing the NuSTAR data pinpoint the most energetic spots. During the observations, microflares went off, which are smaller versions of the larger flares that also erupt from the sun's surface. The microflares rapidly release energy and heat the material in the active regions.

Source: NASA

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NASA-led Study Explains How Black Holes Shine in Hard X-rays

Astronomers continue to develop computer simulations to help future observatories better home in on black holes, the most elusive inhabitants of the universe.

Though black holes likely exist abundantly in the universe, they are notoriously hard to see. Scientists did not capture the first radio image of a black hole until 2019, and only about four dozen black hole mergers have been detected through their signature gravitational ripples since the first detection in 2015.

So scientists look to black hole simulations to gain crucial insight that will help find more mergers with future missions. 

Some of these simulations, created by scientists like astrophysicist Scott Noble, track supermassive black hole binary systems. That is where two monster black holes like those found in the centers of galaxies orbit closely around each other until they eventually merge.

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What Comes After Photographing a Black Hole's Event Horizon? Could we see the Photon Ring?

In 2019 the Event Horizon Telescope (EHT) gave us the first direct image of a black hole. On one hand, the image it produced was rather unimpressive. Just a circular blur of light surrounding a dark central region. On the other hand, subtle characteristics of the image hold tremendous information about the size and rotation of the black hole. Most of the details of the black hole image are blurred by the limits of the EHT. But the next generation EHT should provide a sharper view, and could reveal the dark edge of a black hole’s event horizon.

A black hole doesn’t emit light itself. Any light that crosses its event horizon is forever trapped. The glowing ring we see in the EHT image of M87* is caused by the background radio glow of gas and dust surrounding the black hole. Some of that light passes very close to the black hole and is gravitationally lensed in our direction. The closest limit that light can graze the black hole and reach us is known as the photon ring.

If we could observe the black hole perfectly, the photon ring would be a thin bright line. Some of the light from the photon ring is scattered before it reaches us, and combined with the resolution limits of the EHT this creates the blurred image we see. But the next generation EHT will have a higher resolution and will be able to capture images in a shorter period of time. This will allow detailed images not just of M87*, but also of the supermassive black hole in our galaxy.

One of the things the ngEHT could reveal is multiple layers of lensed light. Most of the light we see surrounding the black hole is that of the photon ring. That is, the strongly lensed light that grazed the black hole. But some light will make a full loop around the black hole before heading our way, and a small amount will make multiple loops. Each type of photon path creates a different layer of light ring around the black hole. If we can pull apart these layers, we will better understand the nature of gravity near a black hole.

The gravitational field near a black hole is so strong that it distorts not only the glow of the photon ring but also the shadow of the event horizon. So while the event horizon is truly spherical, our view of the event horizon can be distorted by the black hole’s gravity. In this latest work, the team shows how we might be able to observe both the photon ring and the inner shadow. By comparing the two we would gain a deep understanding of black hole dynamics, including information about how light and matter are captured by a black hole.

In time, we might finally be able to see the dark shadow of gravity itself.

Source: Univese Today

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Detecting X-Rays From Uranus

Astronomers have detected X-rays from Uranus for the first time, using NASA’s Chandra X-ray Observatory, as shown in this image from March 2021.

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Moon and Jupiter meeting

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Milkyway - Phrygia Valley / Turkey

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Accidental camera flash, but it’s awesome

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This equation will change how you see the world

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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.

It just so happens that the lead researcher on the project, Dr. Miguel Alarcón is from that set of islands off the west coast of Africa. The paper he and his colleagues wrote, soon to be published in The Astronomical Journal, used a series of photometers, confusing called TESS (shown in the first picture) to try to get a baseline of how dark the night sky is throughout the world.

The team collected 11 million points of data from places as far apart as Namibia, Australia, and the US.  While this did not include some more popular astronomy spots, such as the highlands of Antarctica, it was a good sample of different conditions. As mentioned above, the Canary Islands had the lowest levels of background light of anywhere studied.  Only about 2% of the light in the sky at night comes from artificial light at the Roque de los Muchachos Observatory in Garafia.  

However, there are other, natural sources of light pollution that affect different geographies differently.  The moon and the milky way are standard features of the night sky and certainly contribute to the natural brightness of it.  However, there are other, more variable sources that this study monitored.  These include a glow in the upper atmosphere that is caused by a combination of factors, such as the solar cycle, geographical location, and the time of year.

Another source is known as the “gegenschein” or the anti-solar point, directly opposite from the sun in the night sky.  This can only be seen in extremely dark places, and the astronomy institute on the Canary Islands (IAC) is one of them.

Example of different types of light sources in the night sky, including the gegenschein effect. Credit: Juan Carlos Casado

Just because it has some of the darkest skies does not mean it’s the best place for all observations though.  Other factors, such as atmospheric seeing and temperature fluctuations can cause problems with observations.  

The real take away from this research is that if you truly want to see the night sky as our ancestors did, it might be worth a trip to some islands off the coast of Africa.

Vertical panorama showing the night sky over the Canary Islands. Credit: Juan Carlos Casado

Source: The post Astronomers Measure the Background Brightness of the Night sky Across the World. Canary Islands are the Darkest in the Survey appeared first on Universe Today.

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Taking to the Air and Sea to Study Ocean Eddies

The Sub-Mesoscale Ocean Dynamics Experiment (S-MODE) mission team hopes to learn more about small-scale movements of ocean water such as eddies.

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Hubble Gazes at a Cluster Full of Cosmic Clues

This detailed image features Abell 3827, a galaxy cluster that offers a wealth of exciting possibilities for study. Hubble observed it in order to study dark matter, which is one of the greatest puzzles cosmologists face today. 

The science team used Hubble’s Advanced Camera for Surveys and Wide Field Camera 3 to complete their observations. The two cameras have different specifications and can observe different parts of the electromagnetic spectrum, so using them both allowed the astronomers to collect more complete information. Hubble also observed Abell 3827 previously because of the interesting gravitational lens at its core.

Looking at this cluster of hundreds of galaxies, it is amazing to recall that less than 100 years ago, many astronomers thought the Milky Way was the only galaxy in the universe. Although astronomers debated the existence of other galaxies, it took Edwin Hubble’s observations of the Great Andromeda Nebula to confirm that it was in fact far too distant to be part of the Milky Way. The Great Andromeda Nebula became the Andromeda Galaxy, and astronomers recognized that our universe was much, much bigger than humanity had envisioned. 

We can only imagine how Edwin Hubble – after whom the Hubble Space Telescope is named – would have felt if he’d seen this spectacular image of Abell 3827.

Source: NASA

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It's a hotel area on a very crisp -35C evening in Finnish Lapland. He found this tree, & waits, when the aurora came out in the perfect spot.

Archer spent about an hour because of the harsh conditions, but by then he called it a night.

Photo by Tom Archer/2020 Astronomy Photographer of the Year.