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AstronomyAstronomy

Astronomy

May 2019

The world's best-selling astronomy magazine offers you the most exciting, visually stunning, and timely coverage of the heavens above. Each monthly issue includes expert science reporting, vivid color photography, complete sky coverage, spot-on observing tips, informative telescope reviews, and much more! All this in a user-friendly style that's perfect for astronomers at any level.

Land:
United States
Sprog:
English
Udgiver:
Kalmbach Publishing Co. - Magazines
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12 Udgivelser

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early earth’s habitat for life

Where did the water on Earth come from?If you’re like me, having attended school a pretty long time ago, then you probably vaguely remember your earth science classes. Back then, they undoubtedly depicted a molten, hot infant Earth, overrun with lava and boiling proto-oceans. Research over the past decade or two has shown that nothing could be further from the truth.Early Earth was not only cooler than scientists thought for a long time, but it also was a far more hospitable place for life, we believe, much earlier than previously thought. The really scary part of the early history of our planet came not from boiling oceans and uncontrolled volcanoes, but from the so-called Late Heavy Bombardment. This period of frequent major asteroid strikes some 4 billion years ago was…

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astro letters

Halted spaceflightYour recounting of the Apollo era in the December 2018 issue brought back many memories. In the fall of 1968, I was a freshman aerospace engineering student with dreams of exploring the solar system. Those dreams never came true for me, but I am still an active aerospace engineer.My experiences with all things aerospace have convinced me of the technical reasons why humans haven’t ventured beyond low Earth orbit since Apollo. Simply put, chemical rockets are too puny to do the job. And since they are already operating close to the theoretical limits, the situation will not improve as long as they remain the only way into low Earth orbit. When nuclear propulsion cycles for boosters become a topic acceptable for polite discussions, then spaceflight can become as “easy”…

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fresh ice

Mars is cold and mostly dry, a place where liquid water cannot last. But water ice does exist on the Red Planet, and in the northern lowlands, Korolev Crater holds a veritable reservoir nearly 1.1 miles (1.8 kilometers) thick in some places. This remarkable photograph combines five different image strips recorded by the European Space Agency’s Mars Express orbiter, which used its High Resolution Stereo Camera to reveal the 51-mile-wide (82 km) crater and its ever-present sheet of ice.Korolev’s floor stays continuously icy throughout the martian year thanks to the “cold trap” phenomenon in which ice on the crater floor, some 1.2 miles (2 km) below its rim, causes air moving over the ice to cool and sink. This cold layer of air maintains a thin, chilly barrier over the…

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astronomers map a black hole with ‘echoes’ of light

On March 11, 2018, a previously unnoticed black hole flared to life. Using NASA’s Neutron star Interior Composition Explorer (NICER) aboard the International Space Station, a team led by Erin Kara of the University of Maryland and NASA’s Goddard Space Flight Center mapped the region around the black hole in better detail than in any other such object. Their work was published January 9 in Nature; Kara also presented the results during the 233rd meeting of the American Astronomical Society in Seattle.Echoes of lightThe 10-solar-mass black hole, MAXI J1820+070 (J1820 for short), is surrounded by an accretion disk of material from a companion star. Astronomers believe the outburst occurred when an instability caused matter to flood inward. The black hole is also surrounded by a corona of electrons, protons, and…

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what causes meteor showers?

COSMIC RAIN. Watching a meteor streak across the sky is one of the most breathtaking sights a stargazer can experience. However, the challenge is catching one. Although a rogue meteor can zip through our atmosphere at any moment, there are certain times each year when the number of visible meteors skyrockets. Earth’s orbit around the Sun carries our planet through a cloud of cosmic debris left over by a disintegrating comet. And since many comets intersect Earth’s orbit, there is no shortage of showers.FAST FACTThe Eta Aquariid meteor shower, which peaks the night of May ⅚, is associated with debris from the famed Halley’s Comet, which orbits the Sun about once every 75 years.…

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chang’e-4 craft lands on moon’s farside

For the first time in history, humans have softly landed a spacecraft on the farside of the Moon. On January 3 at 10:26 A.M. Beijing time, China’s Chang’e-4 mission made a successful landing in Von Kármán Crater, in the Moon’s South Pole-Aitken basin. Within just a few hours of landing, the craft sent back the first close-up images of the lunar farside.In the following days, the Chang’e-4 mission accomplished another historic first when it successfully sprouted cotton seeds within a protective capsule as part of an onboard mini-biosphere experiment. Unfortunately, the plants quickly died as freezing temperatures washed over the Moon’s farside during its transition from day to night. Though some had optimistically suggested the experiment might last up to 100 days, the 200-plus hours the plants actually survived still…

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