Astronomy September 2014

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.

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3 minutos
reflections on the milky way

W hen I frst got into astronomy in the mid- 1970s, one of the things that grabbed me most signifcantly was observing night afer night in back of our house. On summer nights, the long arch of the Milky Way, stretching from Cassiopeia in the north through Cygnus and all the way down into Scorpius and Sagittarius in the south, was amazing. Filled with glistening stars and pockmarked by rifs of dark nebulae, it was mesmerizing During those first few weeks of my astronomy hobby, I didn’t really grasp entirely what I was looking at. And for most of the history of astronomy, no one did. Only in 1923 did Edwin Hubble discover the true nature of galaxies, which for decades beforehand were thought to be “spiral nebulae” and within our…

2 minutos
why isn’t pluto a planet?

Should location matter this much in defining an object? OK, I’ll admit it — I knew Clyde Tombaugh and observed with him a number of times. But what follows I think of as objective: The discoverer of Pluto deserves a bit better logic than we’ve had thus far. In 2006, the International Astronomical Union (IAU) “demoted” Pluto to dwarf planet status after more Pluto-like objects started to be found in the Kuiper Belt, a region of small icy bodies. And not for good reason. The IAU definition of “planet” came to mean a body 1) orbiting the Sun; 2) large enough to achieve hydrostatic equilibrium — in other words, to be spherical; and 3) able to clear out its orbit of smaller objects. It’s point #3 where Pluto fails. The meaning has changed…

1 minutos
bright heart of darkness

The binary system Cygnus X-1 contains two notable objects: a 9th-magnitude blue supergiant star (the brighter of the two suns at left of center) and a black hole possessing 15 times the Sun’s mass. The black hole’s powerful gravity siphons gas from the supergiant. Most of this incoming material forms a superhot accretion disk that powers X-ray emission, but magnetic fields channel some of it into high-speed jets. Although the black hole, accretion disk, and jets don’t show up in this image, the umbrella-shaped bluish glow at lower right marks where one jet rams into the surrounding interstellar gas. T. A. RECTOR (UNIVERSITY OF ALASKA, ANCHORAGE) AND H. SCHWEIKER (WIYN AND NOAO/AURA/NSF)…

2 minutos
strange universe

Surely astronomers are too courteous to get worked up over celestial arguments. Think again. Scientists on the “wrong side” of a dispute, like the dark matter versus Modified Newtonian Dynamics controversy I explored in the April Astronomy cover story, sometimes find themselves shunned. Tempers can flare. Well, there’s an old journalism adage that “controversy sells.” It’s juicy. So let’s review some famous standout astro-squabbles. We’ll ignore many of the high-blood-pressure incidents of earlier centuries, such as when Galileo Galilei and Christoph Scheiner spent decades during the 1600s putting each other down in print, each claiming to be the first to discover sunspots and having different theories on their origins. The seemingly endless arguments about these solar blemishes continued in the 19th century. Some said sunspots were islands in a sea of glowing…

2 minutos
from our inbox

Aperture upgrade In Bob Berman’s April Astronomy column (p. 11), he described his “first star memory.” Mine is similar. When I was 9 years old, I would sit on our front steps and watch the three stars of Orion’s Belt rise over our neighbors’ house. A short time later, I bought my first telescope — out of a comic book, of all places — for a grand total of about $3. It was a cardboard tube affair with a 1.25- inch aperture. On a clear day, I could almost see objects across the street! I’m 72 now, and fortunately I’ve upgraded to an 8-inch Schmidt-Cassegrain. — Wallace Horn, Madison, Alabama In the other camp was the notion of a sudden birth of everything from a kind of cosmic egg. Edgar Allen Poe…

2 minutos
solving a magnetar mystery

MAGNETAR MATE. Astronomers have for the first time demonstrated that a magnetar — a type of neutron star with an extremely strong magnetic field, as illustrated here — probably formed as part of a binary star system. ESO/L. When a massive star reaches the end of its life and explodes as a supernova, it leaves behind either a neutron star or a black hole. Some of these neutron stars, which are characterized by their small sizes and extreme densities, have enormously powerful magnetic fields and have been named magnetars. But scientists have struggled to figure out how these super-magnetic stellar remnants form. A recent study published in the May issue of Astronomy & Astrophysics could provide a clue. The Westerlund 1 star cluster is home to one of some two dozen magnetars known…