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Jack Horkheimer: Star Gazer

Star Gazer is the world's only weekly television series on naked eye astronomy. Each weekly episode features selected objects for naked eye viewing for the following week. This video podcast contains the 10 most recent episodes of Jack Horkheimer: Star Gazer.

FaviconStar Gazers 1 Min. Dec. 30, 2013- Jan 5, 2013 13 Nov 2013, 4:10 pm

Here Comes The Sun

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FaviconStar Gazers 5 Min. Dec. 30, 2013- Jan 5, 2013 13 Nov 2013, 4:09 pm

Here Comes The Sun

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FaviconStar Gazers 1 Min. Dec. 23-29, 2013 13 Nov 2013, 4:08 pm

Bye-Bye Venus,Good-bye And Celebrate The New Year With The New Year's Eve Star

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FaviconStar Gazers 5 Min. Dec. 23-29, 2013 13 Nov 2013, 4:06 pm

Bye-Bye Venus,Good-bye And Celebrate The New Year With The New Year's Eve Star

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FaviconStar Gazers 1 Min. Dec. 16-22, 2013 13 Nov 2013, 4:03 pm

Off To The Races With Venus And Jupiter

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Science @ NASA Feature Stories Podcast

The mission of Science@NASA is to help the public understand how exciting NASA research is and to help NASA scientists fulfill their outreach responsibilities.

FaviconGeminid Meteors Defy Explanation 9 Dec 2010, 3:00 pm

The annual Geminid meteor shower peaks this year on Dec. 13th and 14th. Researchers don't fully understand the Geminids, and new measurements make it more mysterious than ever.

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Favicon"Arsenic-Bug" Redefines Life as We Know It 2 Dec 2010, 3:00 pm

NASA-supported researchers have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism, which lives in California's Mono Lake, substitutes arsenic for phosphorus in the backbone of its DNA.

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FaviconAlien Comets Invade the Solar System 23 Nov 2010, 3:00 pm

Some of the comets in our Solar System probably came from other stars, according to new research by NASA-supported scientists. Studying these 'alien' comets, they say, could reveal new information about stellar systems far, far away.

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FaviconHubble Observes Possible Asteroid Collision 13 Oct 2010, 2:00 am

NASA's Hubble Space Telescope has captured rare images of a suspected asteroid collision. The snapshots show a bizarre X-shaped object at the head of a comet-like trail of material. Their findings will be published in the Oct. 14th issue of Nature.

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StarDate Online

FaviconDark Center 29 Jul 2014, 1:00 am

A blob of gas spreads out and heats up as it circles the supermassive black hole at the center of the Milky Way galaxy. Known as Sagittarius A-star, the black hole is about 4.2 million times as massive as the Sun and is about 27,000 light-years away. It is normally very "quiet," but it occasionally flares up as material funnels toward it. [ESO/APEX/2MASS/A. Eckart et al./L. Calçada]

Artist's concept of hot gas funneling toward black hole at center of Milky Way

Text ©2014 The University of Texas at Austin McDonald Observatory

For more skywatching tips, astronomy news, and much more, read StarDate magazine.
The one constant in the Universe: StarDate magazine

FaviconDark Center 29 Jul 2014, 1:00 am

The heaviest single object in the entire galaxy is also one of the most difficult to see because it produces no energy at all. But it reveals its presence through its effects on the stars and gas around it.

The object is Sagittarius A-star, a black hole that’s four million times as massive as the Sun. Gravity squeezes it so tightly that nothing can escape it — including light.

The black hole sits at the center of the galaxy, where it’s orbited by stars and gas clouds. Stars move much faster when they’re close to the black hole than when they’re farther away. From that, astronomers calculate the mass of the object the stars are orbiting.

Although the black hole is completely dark, matter around it produces a faint X-ray glow — wisps of gas that are heated as they spiral toward the black hole. And that zone occasionally flares up when an asteroid or other chunk of matter falls into the black hole.

Eventually, astronomers hope to see the black hole itself as a dark outline against the background of stars and gas. Until then, they’ll have to settle for looking at its powerful effects on the center of the galaxy.

And the galaxy’s center is in Sagittarius, which scoots low across the south on summer nights. We can’t see the center with our eyes because it’s hidden behind clouds of dust. It takes special instruments to peer through the dust and behold the wonders in the heart of the Milky Way.

More about those wonders tomorrow.

 

Script by Damond Benningfield, Copyright 2014

For more skywatching tips, astronomy news, and much more, read StarDate magazine.
The one constant in the Universe: StarDate magazine

FaviconThe Brick 28 Jul 2014, 1:00 am

The center of the Milky Way is already crowded with stars. But in a few million years, tens of thousands more could flare to life in a region known as the Brick. It’s a vast cloud of cold, dark gas and dust that’s shaped like a brick.

The Brick may be the biggest future star cluster in the entire galaxy. It’s more than a hundred thousand times the mass of the Sun. And recent observations with a giant new radio telescope show that it contains at least 50 dense blobs of material — embryos that could be giving birth to stars even now.

Stars are born when such blobs collapse under their own gravitational pull. As a blob collapses, it gets hotter. If it gets hot enough, nuclear fusion ignites at its center — giving birth to a star.

There are indications that a few small stars have already formed in the Brick. But such giant clouds are also where big, heavy stars are born — stars that shine tens of thousands of times brighter than the Sun.

It’s not certain that the Brick will give birth to many stars at all, though. While it has the right ingredients, it’s in the busiest, most crowded region of the galaxy. The gravity of the stars and clouds around it could keep it too stirred up to form stars. Powerful magnetic fields could hinder star formation as well.

Astronomers will study the Brick in more detail in the coming years to determine whether it’s the site of future fireworks — or a dark galactic dud.

More about the heart of the Milky Way tomorrow.

 

Script by Damond Benningfield, Copyright 2014

For more skywatching tips, astronomy news, and much more, read StarDate magazine.
The one constant in the Universe: StarDate magazine

FaviconGalactic Track 27 Jul 2014, 1:00 am

Big clouds of gas and dust appear to be taking a roller-coaster ride around the center of the Milky Way galaxy. The oval track is about 600 light-years long by 400 light-years wide, with a big hump on each side of the track.

The track was discovered a few years ago in images from the Herschel space telescope, which looked at the infrared glow of the galaxy’s heart. Cool clouds of gas and dust shine brightest in the infrared.

The observations revealed several big clouds that outline the ring-like structure. The clouds are moving along the track at a couple of hundred thousand miles per hour. In all, they contain enough gas and dust to make about 30 million stars as massive as the Sun.

In fact, new stars are already being born at the ends of the track. In those locations, the outer edges of the gas clouds may interact with clouds that orbit a little farther from the galactic center. That may create shock waves that ripple through the clouds. The shock waves can squeeze knots of gas within the clouds, causing them to collapse to make new stars.

One of the biggest clouds is still dark — it’s given birth to only a few stars at most. And in the turbulent center of the galaxy, it may remain dark. But it could also turn into one of the most impressive stellar nurseries in the entire Milky Way — a cluster of thousands of stars lighting up the busy galactic center. We’ll have more about that tomorrow.

 

Script by Damond Benningfield, Copyright 2014

For more skywatching tips, astronomy news, and much more, read StarDate magazine.
The one constant in the Universe: StarDate magazine

FaviconOld Family 26 Jul 2014, 1:00 am

When a typical star cluster is born, it’s a tightly packed family — hundreds of stars that were born from the same big cloud of gas and dust, all jammed into a fairly small volume of space. As the cluster orbits the center of the galaxy, though, the stars tend to head their separate ways. The cluster is pulled apart by the gravity of the rest of the galaxy, and pushed apart by interactions between members of the cluster itself. So within a billion years or so, most clusters fall apart.

A rare exception is Ruprecht 147, a cluster in Sagittarius. The constellation is in the south this evening, with its brightest stars forming a teapot. Ruprecht 147 is to the upper left of the teapot’s handle, although you need a telescope to see it.

The cluster was discovered in 1830, but until recently it was largely ignored. A few years ago, though, astronomers began studying the cluster in detail. To their surprise, they found that its stars are roughly two-and-a-half billion years old — much older than the typical cluster.

That’s important because clusters are great stellar laboratories. Since the stars in a cluster were all born at the same time, from the same mixture of ingredients, studying how they look today reveals important details about how all stars evolve. So Ruprecht 147 is a rare cluster that provides a look at stars that are well into middle age — a special insight into the lives of the stars.

More about Sagittarius tomorrow.

 

Script by Damond Benningfield, Copyright 2014

For more skywatching tips, astronomy news, and much more, read StarDate magazine.
The one constant in the Universe: StarDate magazine

ESOcast HD

ESOcast is a video podcast series dedicated to bringing you the latest news and research from ESO, the European Southern Observatory. Here we explore the Universe's ultimate frontier with our host Doctor J, a.k.a. Dr. Joe Liske.

FaviconESOcast 66: A Groundbreaking Event for the E-ELT 2 Jul 2014, 9:00 am

On 19 June 2014, a major milestone on the road to the construction of the European Extremely Large Telescope was reached. Part of the 3000-metre peak of Cerro Armazones was blasted away as a step towards levelling the summit. This paves the way for the largest optical/infrared telescope in the world.

FaviconESOcast 65: The Chilean Sky in Ultra High Definition 30 May 2014, 12:00 pm

In the Spring of 2014, a team of ESO Photo ambassadors embarked on a pioneering expedition to ESO's three observatories in Chile. Their mission was to capture a wide range of images and time-lapses of the magnificent Chilean night sky and landscape in crisp Ultra High Definition. Join our heroes in their adventures in the arid Atacama Desert as they bring our Universe closer than ever before.

FaviconESOcast 64: First Ring System Around Asteroid 26 Mar 2014, 2:00 pm

This ESOcast shows how observations at many sites in South America, including ESO's La Silla Observatory, have made the surprise discovery that the remote asteroid Chariklo is surrounded by two dense and narrow rings.

FaviconESOcast 63: Flexible Giants — The Evolution of Telescope Mirrors 19 Feb 2014, 5:00 am

The clear night sky offers one of the most beautiful views in nature. The eye adapts to the dark and the pupil widens to collect more light and thus allow fainter stars to become visible. But the light-collecting area of the human eye is tiny. To peer much deeper into the night sky astronomers need telescopes with enormous primary mirrors to do a much better job.

FaviconESOcast 62: Three planets found in star cluster 15 Jan 2014, 6:00 am

In this ESOcast we look at how astronomers have used ESO's HARPS planet hunter in Chile, along with other telescopes around the world, to discover three planets orbiting stars in the cluster Messier 67. Although more than one thousand planets outside the Solar System are now confirmed, only a handful have been found in star clusters. Remarkably one of these new exoplanets is orbiting a star that is a rare solar twin — a star that is almost identical to the Sun in all respects.

HD - NASA's Jet Propulsion Laboratory

High-definition (HD) videos from NASA's Jet Propulsion Laboratory feature the latest news on space and science findings from JPL and NASA. Topics include discoveries made by spacecraft studying planets in our solar system, including Mars, Saturn and our home planet, Earth. Missions also study stars and galaxies in our universe.

FaviconFlash from Curiosity Rover's Laser Hitting a Martian Rock 16 Jul 2014, 3:00 am



The sparks that appear on the baseball-sized rock result from the laser of the ChemCam instrument on NASA's Curiosity Mars rover hitting the rock.



FaviconNEOWISE Spies Comet Pan-STARRS Against Galaxy Backdrop 3 Jul 2014, 3:00 am



NASA's NEOWISE mission captured a series of infrared images of comet C/2012 K1 -- also referred to as comet Pan-STARRS -- as it swept across our skies in May 2014.



FaviconLDSD Test Vehicle Returns 2 Jul 2014, 3:00 am



NASA's saucer-shaped test vehicle, the Low-Density Supersonic Decelerator (LDSD) was recovered from the ocean and returned to Port Allen, Kauai, on June 29, 2014



FaviconWhat's Up - July 2014 30 Jun 2014, 3:00 am



Spot Pluto and see the Milky Way and planets all month long.



FaviconCassini Arrival at Saturn 24 Jun 2014, 3:00 am



A look back at Cassini's arrival at Saturn.