Astronomy December 2018

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.

United States
Kalmbach Publishing Co. - Magazines
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12 Issues

in this issue

2 min.
celebrating apollo

With this issue, we begin to commemorate one of the greatest anniversaries associated with the exploration of space. Fifty years ago, the Apollo program, which landed humans on the Moon for the first time, succeeded with its first trans-lunar flight, Apollo 8. That craft, piloted by Frank Borman, James Lovell, and Bill Anders, swung around the Moon and returned to Earth, in a dress rehearsal for the Apollo missions to come. Over the coming months, Astronomy will celebrate 50th anniversaries of the Apollo missions with a variety of special features and stories. In this issue, we present Senior Editor Rich Talcott’s detailed interview with Jim Lovell, now 90 years old and as sharp as ever, centering on the experience of Apollo 8. Whether you were alive at the time of Apollo 8 or…

2 min.

Image vs. impression In your Snapshot article, “The first interstellar asteroid,” in the April issue, you commit the cardinal sin of not labeling an artist’s drawing as such. Neither the caption nor the story indicates that the picture of ‘Oumuamua is an artist’s impression, not a real image. I’m sure you, too, have been annoyed at mainstream, non-scientific news sources implying that we’ve captured actual images of objects, like Earth-like exoplanets. Please assure me that this was a one-time oversight. — Ray Gedaly, The Woodlands, TX Escape velocity and acceleration I was reading an article on page 13 of the July 2018 issue of Astronomy that’s titled “How fast must a rocket travel to leave each planet?” but that’s not the same as escape velocity, which is what the speedometer shows. A rocket doesn’t…

1 min.
rubble pile

The Japanese Aerospace Exploration Agency’s Hayabusa2 spacecraft arrived at the near-Earth asteroid Ryugu on June 27. The craft set off on its 3.26 billionmile (5.24 billion kilometers) round-trip journey in late 2014. When Hayabusa2 arrived, mission scientists used images like this one, taken July 20 from a distance of just under 4 miles (6 km), to scope out a landing site for the spacecraft’s Mobile Asteroid Surface Scout (MASCOT). The probe will use an array of instruments, including the MASCOT lander and three small rovers, to dissect the diamond-shaped asteroid’s composition, study its physical properties, and, most excitingly, shoot a projectile into the asteroid’s surface to eject pieces small enough to bring back to Earth. Since asteroids have remained more or less unchanged since their creation, their compositions allow astronomers to…

3 min.
nasa probe will touch the sun

While the Sun might seem an easy target for astronomers, it still harbors numerous mysteries. One is the nature of its corona — the thin, outermost layer of the Sun’s atmosphere, visible from Earth only during a total solar eclipse. Stretching millions of miles and reaching temperatures above 2 million degrees Fahrenheit (1 million degrees Celsius), the corona is perplexingly 300 times hotter than the Sun’s so-called surface, 1,000 miles (1,600 kilometers) below. Launched August 12 from Cape Canaveral, Florida, NASA’s Parker Solar Probe will become the first spacecraft to fly through the blistering gas, returning measurements from within this poorly understood region of our star’s atmosphere. The probe will loop the Sun more than 20 times in seven years, approaching as close as 3.9 million miles (6.2 million km) —…

1 min.
how many craters on jupiter’s moons?

METEORITE MARKS. The Italian astronomer Galileo Galilei discovered the four largest moons of Jupiter in 1610. As telescopes improved, we began to see features on those moons, although we couldn’t spot them clearly. Then, in 1979, the two Voyager spacecraft flew by the jovian system, and we began to map their surfaces. Subsequent spacecraft have added to the picture. — Michael E. Bakich FAST FACT Io has no sizable craters because its volcanoes continually restructure the moon’s surface.…

3 min.
star’s black hole encounter confirms einstein’s theory

Sagittarius A*, the supermassive black hole that dwells in the center of the Milky Way, is about 4 million times the mass of our Sun. Astronomers have long kept their eyes on a mysterious group of high-speed stars that circle it. On May 19, one of those stars, called S2, passed through the black hole’s gravitational field. The event was recorded in incredible detail, and it gave scientists a prime opportunity to study whether a phenomenon predicted by Einstein’s theory of general relativity, dubbed gravitational redshift, takes place under the most extreme cases. And, it turns out, it does. Gravitational redshift happens as light travels through an intense gravitational field and loses some of its energy, causing it to shift toward the red, or less energetic, end of the electromagnetic spectrum. As…