1. Astronomy

Category Archives: Astronomy

Nearby Star 'Alpha Centauri A' May Harbor Rocky Planets; 'Find' Heralds Planet-Hunting Shortcut

Posted on by

NASAs Kepler mission may have made planet-hunting seem easy, but the hard truth is that most of the time looking for planets around other sun-like stars is painstakingly slow. And most of the extrasolar planetary search grunt work is still done on the ground using tried and true methods first put into place some two decades ago.

Enter Ivan Ramirez, an astronomer at the University of Texas at Austin, and colleagues, using the Magellan Clay Telescope in Chile, have taken high-resolution stellar spectra from 88 solar twins that lie within 326 light years of Earth. The hope is that they can prove their hypothesis that these spectra contain signatures of depleted metals caused by the presence of rocky planets. In fact, Ramirez says

In a forthcoming paper in Astronomy & Astrophysics, lead author Ramirez and colleagues note that their idea is that they would actually see less metals in a star that has planets. Ramirez notes that our own Sun has a slightly lower metallicity which Ramirez ascribes to a depletion of certain elements that like to stick together to form rocks.

This artistic image depicts the view from a hypothetical planet orbiting Alpha Centauri A, Alpha Centauri B is clearly seen in the background, as the dimmer star. (Credit: Wikipedia)

Thats how this work started, said Ramirez. We saw this effect first in the Sun and we are extending it to these solar twin stars. Our idea is that these missing rocky elements are in the planets.

Today, says Ramirez, its only possible to measure chemical composition with that kind of precision for stellar solar twins that are roughly the same age, mass and chemical makeup of our sun.

So, instead of calculating how many atoms of titanium are in the target star, said Ramirez, we only care about how much more or less there is compared to the Sun. We look for a depletion of rocky elements relative to non-rocky elements.

Which elements would be missing?

Elements that cover a range of the condensation sequence, said Ramirez, who explains thats the temperature at which such elements change their phase from gas to rock. For example, Ramirez says our own Sun is depleted in specific elements that indicate that we have a planetary system; such as barium, aluminum, iron, magnesium, titanium, chromium, silicon, and yttrium.

The team is still in the process of proving the hypothesis, but has found that five or six stars in the current survey have chemical depletions which could signal planetary systems.

Continue reading here:

Nearby Star 'Alpha Centauri A' May Harbor Rocky Planets; 'Find' Heralds Planet-Hunting Shortcut

Astronomy – Chapter 1: Introduction (4 of 10) Where Did Solar System Come From? – Video

Posted on by


Astronomy - Chapter 1: Introduction (4 of 10) Where Did Solar System Come From?
Visit http://ilectureonline.com for more math and science lectures! In this video I will examine What did all the elements in the universe formed?

By: Michel van Biezen

Follow this link:

Astronomy - Chapter 1: Introduction (4 of 10) Where Did Solar System Come From? - Video

Astronomy – Ch. 2: Understanding the Night Sky (5 of 20) Understanding the Celestial Sphere – Video

Posted on by


Astronomy - Ch. 2: Understanding the Night Sky (5 of 20) Understanding the Celestial Sphere
Visit http://ilectureonline.com for more math and science lectures! In this video I will explain what is the celestial sphere (a sort of GPS of the universe).

By: Michel van Biezen

Read more:

Astronomy - Ch. 2: Understanding the Night Sky (5 of 20) Understanding the Celestial Sphere - Video

Uncloaking the King of the Milky Way: The largest star in our home galaxy's largest stellar nursery

Posted on by

28.08.2014 - (idw) Max-Planck-Institut fr Astronomie

Astronomers led by Shiwei Wu of the Max Planck Institute for Astronomy have identified the most massive star in our home galaxy's largest stellar nursery, the star-forming region W49. The star, named W49nr1, has a mass between 100 and 180 times the mass of the Sun. Only a few dozen of these very massive stars have been identified so far. As seen from Earth, W49 is obscured by dense clouds of dust, and the astronomers had to rely on near-infrared images from ESO's New Technology Telescope and the Large Binocular Telescope to obtain suitable data. The discovery is hoped to shed light on the formation of massive stars, and on the role they play in the biggest star clusters. The discovery of a new, very massive star is exciting to astronomers for more than one reason: Very massive stars, more than 100 times the mass of our own Sun, are something of an astronomical mystery. They are very short-lived (a few million years compared to the 10 billion years of stars like our Sun), which is one reason they are so rare. Among the billions of stars catalogued and examined by astronomers, these very massive specimens amount to no more than a few dozen, most of them discovered over the past few years.

Though rare, the massive stars have a decisive influence on their surroundings. They are extremely bright, giving off large amounts of highly energetic UV radiation as well as streams of particles (stellar wind). Typically, such a star will create a bubble around itself, ionizing any nearby gas, and pushing more distant gas ever farther away. Some of this pushed-away gas might actually cause distant gas clouds to collapse, triggering the birth of new stars.

Until a few years ago, there was even doubt whether such stars could form at all. Theorists have only quite recently managed to simulate the genesis of these massive bodies, and there are now several competing explanations for very massive star formation. In some models, such a star is the result of the merger between two stars forming in an extended star cluster. Up to now, there had only been three clusters (NGC 3603 and the Arches Cluster in our galaxy, R136 in the Large Magellanic Cloud) where such massive stars had actually been found.

Now, a team of astronomers lead by Shiwei Wu from the Max Planck Institute for Astronomy (MPIA) has discovered such a massive star, and not in any location, but in the largest star-forming region known in our Milky Way galaxy, which is called W49. The discovery was a challenging task: W49 is located at a distance of 36,000 light-years (11.1 kpc), almost half-way across our home galaxy, cloaked by the dust of two spiral arms that lie between us and the cluster.

Using a spectrum obtained with the European Southern Observatorys Very Large Telescope in the infrared, the astronomers could determine the stars type (O2-3.5If* star) and use this information and the stars measured brightness to estimate its temperature and total light emission. Comparison with models for stellar evolution give an estimate of the stars mass between 100 and 180 solar masses.

Because of the clusters size, W49 is one of the most important sites within our galaxy for studying the formation and evolution of very massive stars and with W49nr1, the astronomers have now identified the clusters key object. With this and future observations, they have hopes of settling one of astronomys weightiest open questions: the birth of our galaxys most massive stars.

Contact

Shiwei Wu (first author) Max Planck Institute for Astronomy Heidelberg, Germany Phone: (+49|0) 6221 528 203 email: shiwei@mpia.de

Klaus Jger (public information officer) Max Planck Institute for Astronomy Heidelberg, Germany Phone: (+49|0) 6221 528 379 email: pr@mpia.de

Link:

Uncloaking the King of the Milky Way: The largest star in our home galaxy's largest stellar nursery

Tech Lessons From The 'Dark Ages'

Posted on by

The Dark Ages in what is now Western Europesometimes conjure images of a very low-tech society replete with outright barbarism and boiling vats of gruel. But the early Middle Ages (or Dark Ages) a longtime historical pejorative were actually a time of great technological progress, medieval scholars now say.

A scarcity of written records has given rise to the misconception that the early Middle Ages roughly correlating with the end of the Roman Empire Empire in the West (around 476 A.D.) to about 1000 A.D. were unrelentingly primitive, says Benjamin Hudson, a professor of history and medieval studies at Penn State University.

Yet in many ways medievalists were centuries ahead of their time; intrinsically-linked to their landscape and intent on looking for alternative means to harness the power of nature. Part of the Dark Ages image problems, says Hudson, is tied to the nature of scientific development, which in the case of technology was incremental.

Petrarch, who conceived the idea of a European Dark Age. From Cycle of Famous Men and Women, Andrea di Bartolo di Bargilla, c. 1450 (Credit: Wikipedia)

The people making the discoveries often could not read or write, said Hudson. The literate class was the clergy, who had limited interest in science.

The water-powered blast furnace is seen by some as the greatest technological development of the epoch; since it enabled iron to smelt at higher temperatures and much faster and more cheaply than any previous technology.

High-quality horse stirrups were a byproduct of such improved smelting techniques which; as Paolo Squatriti, a medieval historian at the University of Michigan in Ann Arbor, points out, enabled a mounted rider to whack his opponents over the head without falling out of the saddle. This made the knight in shining armor possible, he said.

Although the Classical world that preceded the Dark Ages was aware of basic engineering techniques and energy sources, it depended on slave labor, says Hudson.

Among the Roman [aristocracy] there was an overweening disdain for the mechanical arts, to such an extent that even reading was considered manual labor, said Squatriti. So, you sat back and listened while a slave read to you.

The idea that manual work was bad, says Squatriti, spread with the result that an aristocratic Roman who had the time and resources to devote to the pursuit of technology would never have done such research because he considered it way below his status.

See original here:

Tech Lessons From The 'Dark Ages'

University of Iowa dedicates observatory to James Van Allen

Posted on by

By B.A. Morelli, The Gazette

IOWA CITY The University of Iowa dedicated a revamped observatory with three high-powered telescopes to famed space scientist and longtime UI professor James Van Allen on Friday afternoon.

The 18-foot clamshell dome observatory is mounted high above most of Iowa Citys skyline on the roof of the seven-story Van Allen Hall on campus. The building houses the UI physics and astronomy department that Van Allen helped build.

This combines the technology he loved, and the ability for students to walk one-flight up from the laboratory to use it, said Robert Mutel, a UI physics astronomy professor involved in launching the new observatory.

Van Allen, who died in 2006 at age 91, was a space pioneer who discovered radiation belts that now bear his name.

The old observatory had fallen in disrepair and held outdated technology. It hadnt been used in about 15 years, Mutel said. Students view to the heavens came from remote access to a telescope called Rigel based in Arizona.

With a grant from the Carver Charitable Trust, the department set about returning students access to space research back to arms reach. The new fiberglass structure observatory electronically opens to the sky and at the center three telescopes a solar, planetary and astronomical are fastened together.

The project cost approximately $140,000, including $36,000 for the primary astronomical telescope thats powerful enough to find quasars billions of light years away.

The observatory will primarily be used by students, but the hope is to provide public access as well, such as for astronomy clubs.

Its pretty awe-inspiring, said Erin Maier, a sophomore astronomy and physics student, who helped set up the new observatory and telescopes. We are looking at entire galaxies just like ours in a single image.

Read the rest here:

University of Iowa dedicates observatory to James Van Allen

LACMA exhibition 'African Cosmos' illuminates art of astronomy

Posted on by

First, there was light. Then, a night sky filled with stars and a luminescent moon. Soon after? Art.

Since ancient times, communities have used art to relay stories and make sense of the world around them particularly when interpreting the heavens and giving form to perceived deities ruling the forces of nature.

A new exhibition at the Los Angeles County Museum of Art, "African Cosmos: Stellar Arts," showcases 40 rare objects in gold, silver, bronze, stone, beads and wood that collectively illustrate the history of African cultural astronomy, from ancient Egypt to the present day.

On view is a 4,000-year-old Egyptian Middle Kingdom star clock, carved onto a wooden coffin lid, that marks star patterns. There's a wooden divination board, made by the Yoruba people of Nigeria in the late 19th or 20th century, that was used to connect with the spirit world. A gold "soul washer's disc," more than 100 years old, was made by an Asante artist from Ghana in West Africa and worn by members of the royal court to protect the king and by extension, the nation.

Not all of the works in the show are old: A 2009 video projection by Karel Nel of South Africa incorporates data from a project in which he worked with more than 100 astrophysicists around the world. Called a "cosmic evolution survey," it maps a square patch of the sky south of the constellation Leo.

The exhibition originated at the Smithsonian Institution's National Museum of African Art. It's the second show in LACMA's African Art Gallery, which opened in summer 2013.

Twitter: @debvankin

------------------------------

'African Cosmos: Stellar Arts'

Where: Los Angeles County Museum of Art, 5905 Wilshire Blvd., Los Angeles

Read more:

LACMA exhibition 'African Cosmos' illuminates art of astronomy

KU physics, astronomy department offers fall events

Posted on by

The University of Kansas Department of Physics and Astronomy is having two events this fall in Lawrence that will allow citizen scientists to explore the world and the ever-expanding universe. The events are open to the public and include the following:

From the Smallest to the Biggest: How Our Inward Search Sheds Light on the Earliest Moments of the Universe, 7:30 p.m. Sept. 4 in the Bliss Room at Eldridge Extended, 201 W. Eighth St. Brookhaven National Laboratory scientist Paul Sorensen will discuss everything from the smallest bits of matter created via particle colliders to the largest depths of the expanding universe.

Everyone Loves Science, 7:30 p.m. Oct. 20 at the Lawrence Public Library Auditorium, 707 Vermont St. Physics professor Mats Selen, of the University of Illinois, will lead hands-on, educational physics activities designed to engage attendees and improve learning.

See the original post here:

KU physics, astronomy department offers fall events

Notthingham seminar series takes a look at Big Bang

Posted on by

For 85 years, the Amateur Astronomers Association of Pittsburgh has promoted popular astronomy in Western Pennsylvania and focused on the education of the general public and its members in the science and hobby of astronomy.

To foster this goal, the Mingo Creek Park Observatory in Nottingham scheduled a series of seminars in April of this year, called "The Birth, Life and Death of Stars." Another series of lectures, called "The Big Bang and Then Some,will begin at 7:30 p.m. Sept. 9 and be held on four consecutive Tuesdays.

Bill Roemer, an AAAP member for 18 years from South Fayette, will lead the seminars, starting with "Where We Are and Where Were Going." Session 2 on Sept.16 will take a look at the earliest fraction of time in the history of the universe, called the Planck epoch after Nobel Prize-winning physicist, Max Planck.

"We dont really know what happened at this time and may never know," said Mr. Roemer, former director of Mingo Creek Park Observatory. "Someday quantum mechanics may be able to provide an answer, but at this point we just dont know."

Session 3 on Sept. 23 is about when the universe rapidly expanded and gravity "decoupled" from other forces, which include the strong nuclear force, the weak nuclear force and electromagnetism.

"In the initial Planck epoch, the four fundamental forces were unified and the temperatures were extremely hot," Mr. Roemer said. "Between the times discussed in Session 2 and 3, gravity was no longer unified with the other fundamental forces and temperatures were cooling, and modern physics is now better able to understand what was happening then."

The final session of the series on Sept. 30, "Afterglow," will take the audience up to 10 seconds after the Big Bang and then leap forward to 380,000 years. It will cover the remnants of the Big Bang called the cosmic microwave background, which is still evident in the universe.

Ken Kobus, associate director of the Mingo Creek Park Observatory from BethelPark, said the AAAP is trying to rid people of the notion that they have to understand the math behind the beginning of the universe to understand what happened.

"People should just open up their minds to grasp the logic behind the beginning of the universe," he said. "They might have to listen to the theory a couple of times, but they will be able to understand it without being a mathematician."

Mr. Roemer has a mathematics degree from Youngstown State University and a masters in divinity from the Pittsburgh Theological Seminary. An ordained minister, he is retired but still preaches at different Presbyterian churches almost every Sunday. He also runs Philanthropy Focus Inc., a business that recruits development officers for the nonprofit sector.

See original here:

Notthingham seminar series takes a look at Big Bang

Best View Yet of Merging Galaxies in Distant Universe

Posted on by

Contact Information

Available for logged-in reporters only

Newswise An international team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA) -- among other telescopes -- has obtained the best view yet of a collision between two galaxies when the Universe was only half its current age.

To make this observation, the team also enlisted the help of a gravitational lens, a galaxy-size magnifying glass, to reveal otherwise invisible detail. These new studies of galaxy HATLAS J142935.3-002836 have shown that this complex and distant object looks surprisingly like the comparatively nearby pair of colliding galaxies collectively known as the Antennae.

"While astronomers are often limited by the power of their telescopes, in some cases our ability to see detail is hugely boosted by natural lenses created by the Universe," explains lead author Hugo Messias of the Universidad de Concepcin in Chile and the Centro de Astronomia e Astrofsica da Universidade de Lisboa in Portugal. "Einstein predicted in his theory of General Relativity that, given enough mass, light does not travel in a straight line but will be bent in a similar way to a normal lens."

Cosmic lenses are created by massive structures like galaxies and galaxy clusters, which bend light from objects behind them due to their strong gravity -- an effect called gravitational lensing. The magnifying properties of this effect allow astronomers to study objects that would otherwise be invisible and to directly compare local galaxies with much more remote ones, when the Universe was significantly younger.

For these gravitational lenses to work, however, the foreground lensing galaxy and the one beyond need to be precisely aligned.

"These chance alignments are quite rare and tend to be hard to identify," adds Messias, "but, recent studies have shown that by observing at far-infrared and millimeter wavelengths we can find these cases much more efficiently."

HATLAS J142935.3-002836 (or H1429-0028 for short) is one of these sources and was found in the Herschel Astrophysical Terahertz Large Area Survey (HATLAS). It is among the brightest gravitationally lensed objects in the far-infrared regime found so far, even though we are seeing it at a time when the Universe was just half its current age.

To study this object in further detail, the astronomers started an extensive follow-up campaign using an impressive collection of incredibly powerful telescopes, including the Hubble Space Telescope, ALMA, the Keck Observatory, and the VLA, among others.

See the rest here:

Best View Yet of Merging Galaxies in Distant Universe

Astronomy History and Future Come Together at the South Carolina State Museum

Posted on by

Want to stay on top of all the space news? Follow @universetoday on Twitter

Looking through the historic 12 3/8 refractor. Credit: South Carolina State Museum.

Seeking out science and astronomy in South Carolina? Youre in luck, as were pleased to report the South Carolina State Museums brand-spanking new planetarium and astronomical observatory opened to the public earlier this month. Part of a 75,000 square foot expansion project dubbed Windows to New Worlds, the renovation puts the museum on the cutting edge of STEM education and public outreach. And not only does the new expansion include one of the largest planetariums in the southeastern U.S., but it also features the only 4D theater in the state of South Carolina. The observatory, planetarium and brand new exhibits present a fascinating blend of the grandeur of astronomical history and modern technology.

Exploring the universe Credit: South Carolina State Museum/Sean Rayford.

What we have built represents a quantum leap forward for South Carolina in the areas of cultural tourism, recreation and especially education, said executive director of the South Carolina State Museum Willie Calloway in a recent press release. Our new facility is building opportunity opportunity for students to thrive, opportunity for our economy to grow and opportunity for our guests to be entertained in new ways.

The 12 3/8 refractor prior to installation in the observatory. Photo by author.

We first visited the South Carolina State Museum in 2012when plans for the planetarium and observatory were just starting to come together. The large Alvan Clark refractor now in the observatory was on display in the main museum, but much of the telescopes in the museums collection of antique instruments and gear were yet to be seen by the public.

A collection of eyepieces and adapters from the Robert Ariail collection. Photo by author.

We firmly believe that a telescope out under the night sky is a happy telescope, and its great to see the old 12 3/8 Alvan Clark refractor in action once again!

A brass solar flip adapter. Photo by author.

See original here:

Astronomy History and Future Come Together at the South Carolina State Museum

A Day In The Life of an European Southern Observatory Astronomer – Video

Posted on by


A Day In The Life of an European Southern Observatory Astronomer
Astronomy: Secrets of the Universe Revealed || A Day In The Life of an European Southern Observatory Astronomer Have you ever wondered what it must be like to be an astronomer? In this fourth...

By: Astronomy - Secrets of the Universe Revealed

Read the original here:

A Day In The Life of an European Southern Observatory Astronomer - Video

Green Bank Telescope helps chart underground features on Moon, provide 3-D image of asteroid

Posted on by

The National Radio Astronomy Observatorys Green Bank Telescope in Pocahontas County and the Arecibo Observatorys huge radiotelescope in Puerto Rico teamed up earlier this month to generate images of subterranean rock clusters and changes in the composition of dust up to 50 feet below the surface of the moon.

To produce the images, radar signals beamed from the Arecibo telescopes powerful transmitter penetrated 33 to 50 feet through the lunar surface and rebounded back to Earth, where they were detected by the sensitive receivers on the Green Bank Telescope. One image was taken of a portion of the moons Sea of Serenity, not far from Apollo 17s landing site in 1972. Changes in the composition of lunar dust and differences in the abundance of sub-surface rocks could be seen in the radar observations.

A second image was made of a 34-mile wide, 2-mile deep impact crater known as Aristillus, where a dark, halo-like feature surrounding the crater was determined to have been caused by pulverized debris flying out of the crater. The image also shows traces of lava-like features produced when lunar rock heated during impact flew beyond the perimeter of the crater.

According to a release from the National Radio Astronomy Observatorys headquarters in Charlottesville, Va., the subterranean lunar images will help scientists interpret the history of the moon, which is often obscured by billions of years of dust accumulations. They will also help space program researchers better understand the geology of previous lunar landing sites and plan for future landings on the moon.

In late April, the Green Bank Telescope teamed up with the Arecibo scope to observe a passing asteroid known as 2006 SX 217. Once again, radar pulses from Arecibo were bounced off the asteroid as it passed about 3 million miles from Earth, and then received and decoded by the West Virginia observatory. Since the asteroid was heading away from Earth and into the glare of the sun, optical telescopes were unable to observe its passing.

Because the asteroid is spinning, astronomers will be able to analyze how the returning radar signals are spread out, and after careful analysis, be able to construct a 3-D model of it. Preliminary observations indicated that the asteroid is about 4,000 feet in diameter larger than previously thought and unusually dark. An astronomer at the Arecibo observatory described the asteroids color as being about as black as toner in a copier.

The asteroid will not pass close enough to Earth for similar observations until 2066.

The 305-meter Arecibo radiotelescope, perched atop a limestone sinkhole and the 100-meter, fully steerable Green Bank Telescope have cooperated on a number of similar observations over the years, using a technique known as bi-static radar. In 2001, the West Virginia telescopes first scientific observations of the cloud-shrouded surface of Venus and of a smaller asteroid were made in conjunction with the Puerto Rico telescope, using the bi-static technique.

Both observatories are funded through the National Science Foundation. In 2012, an NSF review committee recommended that the Green Bank Telescope be divested from the portfolio of observatories the NSF funds by 2017, while keeping the older Arecibo scope, completed in 1963.

Reach Rick Steelhammer at 304-348-5169 or rsteelhammer@wvgazette.com.

Original post:

Green Bank Telescope helps chart underground features on Moon, provide 3-D image of asteroid


  1. Astronomy