Recent Astronomy Articles at Cosmic Pursuits

Touring the Heart of the Milky Way – Part 2

August 18, 2017 by Brian Ventrudo Filed Under: Deep Sky

A look at the deep-sky objects in and around Sagittarius covered in this tour. Objects in white font are covered in this tour. Objects in blue font were covered in the last tour. Click to open in a new tab.

Last week, you began a tour of some of the finer sights in and around the Milky Way in the constellation Sagittarius. This week, let’s look slightly westward to see another handful of splendid sights along the Sagittarius Arm of the Milky Way. The tour follows the objects in the white font in the above image. Those in blue font were covered in last week’s tour.

The base of operations for this tour is the grand constellation Scorpius, the Scorpion. The long, winding constellation is one of the few that obviously resembles its namesake. The claws of the fearsome celestial arachnid face westward towards the relatively sparse star fields of the constellation Libra. At the heart of the scorpion lies the bright red-orange supergiant star Antares. And to the east lies the winding tail that passes through increasingly rich star fields towards the heart of the Milky Way Galaxy [Read more…] about Touring the Heart of the Milky Way – Part 2

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Touring the Heart of the Milky Way – Part 1

August 11, 2017 by Brian Ventrudo Filed Under: Deep Sky

The rich and gauzy star fields along the Milky Way towards the constellations Sagittarius and Scorpius constitute what’s arguably the most beautiful part of the night sky. Northern observers can see these constellations well over the southern horizon in the mid-to-late evening hours in August and September, while southern-hemisphere observers see this glorious region nearly overhead. Aim binoculars or a telescope towards this part of the sky, or simply gaze in this direction on a dark night with your unaided eyes, and you will see something good. The trick is figuring out which sight is which. To help you sort it all out, here’s a step-by-step tour of a small selection of the more prominent sights of the deep sky towards the center of the Milky Way [Read more…] about Touring the Heart of the Milky Way – Part 1

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The Sky This Month – August 2017

August 1, 2017 by Brian Ventrudo Filed Under: Celestial Events

Image of the 2015 total solar eclipse over the Faroe Islands. Credit: David Byrne at Flickr.com

2 August. Look for sand-colored Saturn to the south and west of the waxing gibbous Moon, and north and east of the red-orange star Antares. Well past opposition, the planet is still a dazzling sight in a small telescope all month. Its rings are tilted near maximum, about 27º, the greatest in 15 years, and the planet’s disk is still a respectable 18″ across. If you’ve got a telescope, make some time to see Saturn this month. It’s a beautiful sight [Read more…] about The Sky This Month – August 2017

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The Mysterious Hiss from the Milky Way

July 22, 2017 by Brian Ventrudo Filed Under: Science

The northern summer Milky Way. The center of our galaxy lies just above the tree at lower center in this image. The Bell Labs radio engineer Karl Jansky discovered radio emissions from this location in the early 1930s. Image credit: Brian Ventrudo/CosmicPursuits.com.

In the early 1930′s, Bell Labs, the research division of AT&T, launched a project to use radio “short waves” to transmit telephone calls across the Atlantic. The technology to transmit signals via short waves was reasonably well understood. But engineers also needed to understand sources of noise that might interfere with radio communications signals. So the powers-that-were at Bell Labs tasked a young engineer to find sources of radio static that might interfere with transmissions. During his work, this young engineer, Karl Jansky, made an accidental discovery that revolutionized astronomy [Read more…] about The Mysterious Hiss from the Milky Way

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The Distances to the Galaxies

July 10, 2017 by Brian Ventrudo Filed Under: Science

Multiple images by NASA’s Hubble Space Telescope of the Cepheid variable star that in 1923 altered the course of modern astronomy. Called “V1″, it was first detected by Edwin Hubble with the 100” reflector at Mt. Wilson Observatory. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

In our previous stop on our tour of celestial objects of cosmological importance, we looked at a handful of galaxies measured by the early 20th-century astronomer Vesto Slipher. The former Indiana farm boy wrestled with a modestly endowed telescope and a 450-pound spectrometer to make an astonishing discovery. He found the ‘spiral nebulae’ like Andromeda (M31) and the Sombrero (M104) were moving away from us at astonishing speeds, up to 1000 km/s and far faster than any nearby stars. The speeds of these spiral assemblies strongly suggested they lay outside our own group of stars, and were perhaps separate galaxies in their own right far outside our own.

But in science, a strong suggestion is not proof.

In the first years of the 20th century, astronomers had no way of knowing for sure the distance to these spiral assemblies. Indeed, a hundred years ago, they only could estimate the distances to a handful of nearby stars. The true scale of even our own galaxy was a complete mystery. No one knew whether the Milky Way was all there was to the universe, and whether it was a hundred light years across, or a thousand, or a trillion. Never mind the distances to the mysterious ‘spiral nebulae’, which may simply have been nearby star systems in the process of formation.

The key to the distance to the spiral nebulae, which we now know to be separate galaxies, and to the universe itself, lay unexpectedly in a class of unassuming stars, many of which you can see from your backyard with a pair of binoculars or without any optics at all [Read more…] about The Distances to the Galaxies

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