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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

FaviconBeta Cassiopeia 28 Feb 2015, 1:00 am

A bright star in Cassiopeia is in a short but impressive phase of life: it’s beginning to puff up like a giant balloon.

Beta Cassiopeia is in the northwest early this evening, at the bottom of a sideways letter W formed by some of the constellation’s brightest stars.

Beta Cass is probably less than half the age of the Sun. But it’s almost twice as massive as the Sun, so it burns through its nuclear fuel much more quickly. In fact, it’s probably already consumed the original hydrogen fuel in its core, converting it to helium. Gravity is causing the core to shrink and get hotter, which eventually will allow it to start burning the helium to make even heavier elements.

In reaction to the changes in the core, Beta Cass’s outer layers are starting to puff up. Right now, the star is roughly four times the diameter of the Sun. That’s big, but not nearly as big as the star will be. Over millions of years, it’ll puff up to dozens of times the Sun’s diameter. It’ll then shrink and cool a little as it goes through another series of changes, before puffing up to even bigger proportions.

At the end of that second cycle, Beta Cass will shed its outer layers into space, briefly surrounding itself with a glowing bubble of gas and dust. The bubble will quickly dissipate, though, leaving only the star’s now-dead core — a hot but tiny cosmic ember known as a white dwarf: a stellar corpse that will slowly cool and fade away into the long cosmic night.

 

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

FaviconHints of Life 27 Feb 2015, 1:00 am

It’s clear that Mars was much warmer and wetter in the distant past. What’s not so clear is whether any living organisms ever basked in those comfy conditions. The Curiosity rover recently found organic compounds in a rock and bursts of methane in the atmosphere — both of which could be evidence of life. And pieces of the Red Planet continue to show intriguing signs of ancient microscopic life.

Those signs are found in meteorites — pieces of Mars that were blasted into space when large asteroids slammed into the planet, and that later found their way to Earth.

A couple of decades ago, a team of scientists reported evidence of ancient microscopic life in one of these rocks. But many other scientists discounted the findings. Even so, similar evidence has been reported in a few other meteorites over the years.

The most recent came in December. An international team found organic material in one meteorite that appears to have been produced by living organisms.

The meteorite fell in the desert of Morocco in 2011, and pieces of it were quickly recovered. Scientists found possible products of life inside cracks in one of the rocks. They ruled out the possibility that these organic compounds entered the rock after it hit Earth. The team says the most likely source is Martian life.

Mars is in pretty good view in the early evening sky right now. It’s low in the west as night falls, close to the lower right of Venus, the “evening star.”

 

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

FaviconBright Mysteries 26 Feb 2015, 4:04 am

Two bright spots glare from inside a crater on Ceres, the largest member of the asteroid belt. The Dawn spacecraft, which is scheduled to enter orbit around Ceres on March 6, snapped the image from a range of 29,000 miles (46,000 km) on February 19. Scientists have no explanation for the bright spots, although some speculate that they could be volcanic in origin, perhaps pouring fresh ice onto the dwarf planet's surface. [ NASA/JPL/Caltech/UCLA/MPS/DLR/IDA]

Dawn image of mysterious bright spots on Ceres, February 19, 2015

Text ©2015 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

FaviconFewer New Stars 26 Feb 2015, 1:00 am

One of the busiest stellar nurseries in the galaxy stands about half way up the southern sky at nightfall right now. The Orion Nebula has given birth to thousands of stars, with many more taking shape even now.

As the universe has aged, sights like the Orion Nebula have become less common — far fewer stars are born today than when the universe was young.

In fact, the rate at which new stars are born reached its peak billions of years ago, and has been dropping ever since. According to a study published a couple of years ago, the universe is giving birth to only one-thirtieth as many stars today as it did about 11 billion years ago. In fact, the study says that 95 percent of all the stars that will ever be born have already taken shape.

In part, the drop in the stellar birth rate is because much of the original supply of gas for making stars has been used up. The universe is also bigger now, so the gas for making new stars is more spread out. And hot gas around giant black holes creates radiation that may shut down the process of starbirth in many galaxies. Yet these ideas can’t fully account for the dramatic drop in starbirth — leaving astronomers to ponder why so few stars are born today.

Stars are still being born in the Orion Nebula, though. Look for it below the three stars of Orion’s Belt. Under dark skies, the nebula looks like a large but fuzzy star — a massive stellar nursery less than 1400 light-years away.

 

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

FaviconMoon and Aldebaran 25 Feb 2015, 1:00 am

It’s a bit hard to believe when you look at it, but we’re not seeing the star Aldebaran at its best.

Aldebaran is quite close to the lower right of the Moon this evening. It shines brightly even through the lunar glare. In fact, it’s the 14th-brightest star system in the night sky, so it’s always easy to spot.

At visible wavelengths, Aldebaran shines about 150 times brighter than the Sun. That’s mainly because the star is much bigger than the Sun, so there’s a lot more surface area to radiate light into space.

When you add up all wavelengths of light, though, Aldebaran is about 450 times brighter than the Sun. Most of that energy is in the infrared, which is invisible to the human eye.

That, too, is a result of Aldebaran’s great size. The star is nearing the end of its life, causing its outer layers to puff up to giant proportions. As those layers expanded they also got cooler — much cooler than the Sun. That gives Aldebaran its orange color — cooler stars are orange or red, while hotter ones are blue or white.

Cooler stars actually radiate most of their energy at wavelengths beyond the red end of the visible spectrum — the infrared. And that’s the case with Aldebaran. Earth’s atmosphere absorbs most of the infrared energy from stars. But from outside the atmosphere, if our eyes were tuned to the infrared, Aldebaran would look even brighter than it does now. Only then would we see this bright star at its absolute best.

 

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 72 – Looking Deeply into the Universe in 3D 26 Feb 2015, 6:00 am

The MUSE instrument on ESO’s Very Large Telescope has given astronomers the best ever three-dimensional view of the deep Universe. After staring at the Hubble Deep Field South region for a total of 27 hours the new observations reveal the distances, motions and other properties of far more galaxies than ever before in this tiny piece of the sky. But they also go beyond Hubble and reveal many previously unseen objects.

FaviconESOcast 71: New Exoplanet-hunting Telescopes on Paranal 14 Jan 2015, 6:00 am

This ESOcast takes a close look at an unusual new group of small telescopes that has recently achieved first light at ESO’s Paranal Observatory in northern Chile.

FaviconESOcast: 70: Green Light for E-ELT Construction 4 Dec 2014, 6:00 am

The European Extremely Large Telescope, or E-ELT for short, will be by far the largest optical and near-infrared telescope in the world. In early December 2014 the ESO Council gave the go-ahead for the first construction phase of the telescope.

FaviconESOcast 69: Revolutionary ALMA Image Reveals Planetary Genesis 6 Nov 2014, 7:00 am

ESOcast 69 presents the result of the latest ALMA observations, which reveal extraordinarily fine detail that has never been seen before in the planet-forming disc around the young star HL Tauri.

FaviconESOcast 68: ESO Opens its Doors 24 Oct 2014, 11:00 am

On 11 October 2014 the ESO Headquarters in Garching, Germany, once more opened their doors to the public. Some 3 300 people used this special opportunity of the Open House Day to visit the centre of the world's foremost astronomical organisation.

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.

FaviconSoil Moisture Mapper Antenna Deploys 26 Feb 2015, 3:00 am



Get a behind-the-scenes look at the SMAP team at the moment of spacecraft antenna deployment, Feb. 24, 2015.



FaviconReflections on the Pale Blue Dot 13 Feb 2015, 3:00 am



Ann Druyan, Carl Sagan's co-author and widow, reflects on the meaning of Voyager's "pale blue dot" image of Earth.



FaviconCuriosity Rover Report: Rover Walkabout 12 Feb 2015, 3:00 am



Curiosity wraps up an investigation at Pink Cliffs while trying out a style of exploration used by geologists on Earth called "the walkabout."



FaviconWhat's Up - February 2015 4 Feb 2015, 3:00 am



See planetary pairs grace the sky in time for Valentine’s Day and Jupiter’s moons perform a celestial ballet.



FaviconNASA Launches Soil Moisture Mapper 2 Feb 2015, 3:00 am



Highlights from launch, separation and solar array deployment of the SMAP spacecraft.