Moon Near the Edge

Most of us watch the Moon at night. But the Moon spends nearly as many daylight hours above our horizon, though in bright daytime skies the lunar disk looks pale and can be a little harder to see. Of course in daytime skies the Moon also appears to cycle through its phases, shining by reflected sunlight as it orbits our fair planet. For daytime moonwatchers, the Moon is probably easier to spot when the visible sunlit portion of the lunar disk is large and waxing following first quarter or waning approaching its third quarter phase. And though it might look unusual, a daytime moon is often seen even in urban skies. Captured here in a telephoto snapshot taken on March 12, a waxing daytime Moon is aligned near the edge of a popular observation deck that overlooks New York City's borough of Manahattan.

from NASA https://ift.tt/P10dJVT

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The Observable Universe

How far can you see? Everything you can see, and everything you could possibly see, right now, assuming your eyes could detect all types of radiations around you -- is the observable universe . In light, the farthest we can see comes from the cosmic microwave background , a time 13.8 billion years ago when the universe was opaque like thick fog. Some neutrinos and gravitational waves that surround us come from even farther out, but humanity does not yet have the technology to detect them. The featured image illustrates the observable universe on an increasingly compact scale , with the Earth and Sun at the center surrounded by our Solar System , nearby stars , nearby galaxies , distant galaxies , filaments of early matter , and the cosmic microwave background . Cosmologists typically assume that our observable universe is just the nearby part of a greater entity known as "the universe" where the same physics applies. However, there are several lines of popular but spe...

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These three bright nebulae are often featured on telescopic tours of the constellation Sagittarius and the crowded starfields of the central Milky Way . In fact, 18th century cosmic tourist Charles Messier cataloged two of them; M8 , the large nebula below and right of center, and colorful M20 near the top of the frame. The third emission region includes NGC 6559 , left of M8 and separated from the larger nebula by a dark dust lane. All three are stellar nurseries about five thousand light-years or so distant. Over a hundred light-years across the expansive M8 is also known as the Lagoon Nebula. M20's popular moniker is the Trifid. Glowing hydrogen gas creates the dominant red color of the emission nebulae. But for striking contrast, blue hues in the Trifid are due to dust reflected starlight . The broad interstellarscape spans almost 4 degrees or 8 full moons on the sky. from NASA https://ift.tt/3eLgskj

Untitled

Why is our Sun so active now ? No one is sure. An increase in surface activity was expected because our Sun is approaching solar maximum in 2025. However, last month our Sun sprouted more sunspot s than in any month during the entire previous 11-year solar cycle -- and even dating back to 2002. The featured picture is a composite of images taken every day from January to June by NASA 's Solar Dynamic Observatory . Showing a high abundance of sunspots, large individual spots can be tracked across the Sun's disk, left to right, over about two weeks. As a solar cycle continues, sunspots typically appear closer to the equator. Sunspots are just one way that our Sun displays surface activity -- another is flares and coronal mass ejections (CMEs) that expel particles out into the Solar System . Since these particles can affect astronauts and electronics, tracking surface disturbances is of more than aesthetic value . Conversely, solar activity can have very high aesthetic v...

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