David Kirkpatrick

August 28, 2010

Cool space image — Orcus Patera

Filed under: Science — Tags: , , , , , , , , — David Kirkpatrick @ 12:58 pm

Orcus Patera is a crater on Mars with an unusual elongated shape:

From the link:

Orcus Patera is an enigmatic elliptical depression near Mars’s equator, in the eastern hemisphere of the planet. Located between the volcanoes of Elysium Mons and Olympus Mons, its formation remains a mystery.

Often overlooked, this well-defined depression extends approximately 380 km by 140 km in a NNE–SSW direction. It has a rim that rises up to 1800 m above the surrounding plains, while the floor of the depression lies 400–600 m below the surroundings.

Hit this link for a much larger version of the image.

July 13, 2010

Beautiful space image — NGC 2467

Enjoy

Caption: A colorful star-forming region is featured in this stunning new NASA/ESA Hubble Space Telescope image of NGC 2467. Looking like a roiling cauldron of some exotic cosmic brew, huge clouds of gas and dust are sprinkled with bright blue, hot young stars. Strangely shaped dust clouds, resembling spilled liquids, are silhouetted against a colourful background of glowing. Like the familiar Orion Nebula, NGC 2467 is a huge cloud of gas — mostly hydrogen — that serves as an incubator for new stars. This picture was created from images taken with the Wide Field Channel of the Advanced Camera for Surveys through three different filters (F550M, F660N and F658N, shown in blue, green and red). These filters were selected to let through different colours of red and yellow light arising from different elements in the gas. The total aggregate exposure time was about 2000 seconds and the field of view is about 3.5 arcminutes across. These data were taken in 2004.

Credit: NASA, ESA and Orsola De Marco (Macquarie University)

Usage Restrictions: None

Related news release: Hubble snaps sharp image of cosmic concoction

April 9, 2010

Beautiful space image — M 66 of the Leo Triplet

Filed under: et.al., Science — Tags: , , , , , , — David Kirkpatrick @ 2:08 am

A gorgeous galaxy:

Click for larger image

Hubble has snapped a spectacular view of M 66, the largest “player” of the Leo Triplet, and a galaxy with an unusual anatomy: it displays asymmetric spiral arms and an apparently displaced core. The peculiar anatomy is most likely caused by the gravitational pull of the other two members of the trio.

The unusual spiral galaxy, Messier 66, is located at a distance of about 35 million light-years in the constellation of Leo. Together with Messier 65 and NGC 3628, Messier 66 is the member of the Leo Triplet, a trio of interacting spiral galaxies, part of the larger Messier 66 group. Messier 66 wins in size over its fellow triplets — it is about 100 000 light-years across.

Be sure to hit the link up there for an absolutely humongous version of the image. Here’s some additional background.

December 10, 2008

CO2 on extrasolar planet

Exciting news in the search for life beyond our atmosphere.

The release:

Hubble finds carbon dioxide on an extrasolar planet

The NASA/ESA Hubble Space Telescope’s international team of researchers has discovered carbon dioxide in the atmosphere of a planet orbiting another star. This is an important step along the trail of finding the chemical biotracers of extraterrestrial life, as we know it. These findings have been published in the Astrophysical Journal Letters, 9 December 2008.

The Jupiter-sized planet, called HD 189733b, is too hot for life. But new Hubble observations are a proof-of-concept demonstration that the basic chemistry for life can be measured on planets orbiting other stars. Organic compounds can also be a by-product of life processes and their detection on an Earth-like planet may someday provide the first evidence of life beyond Earth.

Previous observations of HD 189733b by Hubble and the Spitzer Space Telescope found water vapour. Earlier this year Hubble found methane in the planet’s atmosphere.

“This is exciting because Hubble is allowing us to see molecules that probe the conditions, chemistry, and composition of atmospheres on other planets,” says Mark Swain of The Jet Propulsion Laboratory in Pasadena, USA. “Thanks to Hubble we’re entering an era where we are rapidly going to expand the number of molecules we know about on other planets.”

Swain and team used Hubble’s Near Infrared Camera and Multi-Object Spectrometer (NICMOS) to study infrared light emitted from the planet, which lies 63 light-years away. Gases in the planet’s atmosphere absorb certain wavelengths of light from the planet’s hot glowing interior. They identified not only carbon dioxide, but also carbon monoxide. The molecules leave their own unique spectral fingerprint on the radiation from the planet that reaches Earth. This is the first time a near-infrared emission spectrum has been obtained for an extrasolar planet.

“The carbon dioxide is kind of the main focus of the excitement, because that is a molecule that under the right circumstances could have a connection to biological activity as it does on Earth,” Swain says. “The very fact that we’re able to detect it, and estimate its abundance, is significant for the long-term effort of characterizing planets both to find out what they’re made of and to find out if they could be a possible host for life.”

Co-researcher, the UK’s Dr Giovanna Tinetti of the University College London, who holds a prestigious Aurora Fellowship at the Science and Technology Facilities Council (STFC) says: “In the terrestrial planets of our solar system, CO2 plays a crucial role in the stability of climate. On Earth, CO2 is one of the ingredients of the photosynthesis and a key element for the carbon cycle. Our observations represent a great opportunity to understand the role of CO2 in the atmospheres of hot-gaseous and highly irradiated planets”.

This type of observation is best done for planets with orbits tilted edge-on to Earth. They routinely pass in front of and then behind their parent stars, phenomena known as eclipses. The planet HD 189733b passes behind its companion star once every 2.2 days. This allows an opportunity to subtract the light of the star alone (when the planet is blocked) from that of the star and planet together prior to eclipse), thus isolating the emission of the planet alone and making possible a chemical analysis of its “day-side” atmosphere.

In this way, Swain explains that he’s using the eclipse of the planet behind the star to probe the planet’s day side, which contains the hottest portions of its atmosphere. “We’re starting to find the molecules and to figure out how many of them there are to see the changes between the day side and the night side,” Swain says.

This successful demonstration of looking at near-infrared light emitted from a planet is very encouraging for astronomers planning to use the NASA/ESA/CSA James Webb Space Telescope when it is launched in 2013. These biomarkers are best seen at near-infrared wavelengths.

Astronomers look forward to using JWST to spectroscopically look for biomarkers on a terrestrial planet the size of Earth, or a “super-Earth” several times our planet’s mass. “The Webb telescope should be able to make much more sensitive measurements of these primary and secondary eclipse events,” Swain says.

Swain next plans to search for molecules in the atmospheres of other extrasolar planets, as well as trying to increase the number of molecules detected in extrasolar planet atmospheres. He also plans to use molecules to study changes that may be present in extrasolar planet atmospheres to learn something about the weather on these distant worlds.

 

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September 23, 2008

Solar wind at 50-year low

Filed under: Science — Tags: , , , , , — David Kirkpatrick @ 1:31 pm

This sounds a bit disturbing to me.

The NASA release:

Ulysses Reveals Global Solar Wind Plasma Output at 50-Year Low

WASHINGTON, Sept. 23 /PRNewswire-USNewswire/ — Data from the Ulysses spacecraft, a joint NASA-European Space Agency mission, show the sun has reduced its output of solar wind to the lowest levels since accurate readings became available. The sun’s current state could reduce the natural shielding that envelops our solar system.

“The sun’s million mile-per-hour solar wind inflates a protective bubble, or heliosphere, around the solar system. It influences how things work here on Earth and even out at the boundary of our solar system where it meets the galaxy,” said Dave McComas, Ulysses’ solar wind instrument principal investigator and senior executive director at the Southwest Research Institute in San Antonio. “Ulysses data indicate the solar wind’s global pressure is the lowest we have seen since the beginning of the space age.”

The sun’s solar wind plasma is a stream of charged particles ejected from the sun’s upper atmosphere. The solar wind interacts with every planet in our solar system. It also defines the border between our solar system and interstellar space.

This border, called the heliopause, surrounds our solar system where the solar wind’s strength is no longer great enough to push back the wind of other stars. The region around the heliopause also acts as a shield for our solar system, warding off a significant portion of the cosmic rays outside the galaxy.

“Galactic cosmic rays carry with them radiation from other parts of our galaxy,” said Ed Smith, NASA’s Ulysses project scientist at the Jet Propulsion Laboratory in Pasadena, Calif. “With the solar wind at an all-time low, there is an excellent chance the heliosphere will diminish in size and strength. If that occurs, more galactic cosmic rays will make it into the inner part of our solar system.”

Galactic cosmic rays are of great interest to NASA. Cosmic rays are linked to engineering decisions for unmanned interplanetary spacecraft and exposure limits for astronauts traveling beyond low-Earth orbit.

In 2007, Ulysses made its third rapid scan of the solar wind and magnetic field from the sun’s south to north pole. When the results were compared with observations from the previous solar cycle, the strength of the solar wind pressure and the magnetic field embedded in the solar wind were found to have decreased by 20 percent. The field strength near the spacecraft has decreased by 36 percent.

“The sun cycles between periods of great activity and lesser activity,” Smith said. “Right now, we are in a period of minimal activity that has stretched on longer than anyone anticipated.”

Ulysses was the first mission to survey the space environment over the sun’s poles. Data Ulysses has returned have forever changed the way scientists view our star and its effects. The venerable spacecraft has lasted more than 18 years, or almost four times its expected mission lifetime. The Ulysses solar wind findings were published in a recent edition of Geophysical Research Letters.

The Ulysses spacecraft was carried into Earth orbit aboard space shuttle Discovery on Oct. 6, 1990. From Earth orbit it was propelled toward Jupiter, passing the planet on Feb. 8, 1992. Jupiter’s immense gravity bent the spacecraft’s flight path downward and away from the plane of the planets’ orbits. This placed Ulysses into a final orbit around the sun that would take it over its north and south poles.

The Ulysses spacecraft was provided by ESA, having been built by Astrium GmbH (formerly Dornier Systems) of Friedrichshafen, Germany. NASA provided the launch vehicle and the upper stage boosters. The U.S. Department of Energy supplied a radioisotope thermoelectric generator to power the spacecraft. Science instruments were provided by U.S. and European investigators. The spacecraft is operated from JPL by a joint NASA-ESA team.

More information about the Ulysses mission is available on the Web at:

http://ulysses.jpl.nasa.gov/.

Source: NASA
   

Web Site:  http://www.nasa.gov/

July 24, 2008

The Hubble finds galaxy cluster lenses

Filed under: Science — Tags: , , , , , , — David Kirkpatrick @ 6:59 pm

This a great press release from NASA and ESA on the latest Hubble Space Telescope news. Hit the link for a weatlth of images, video and additional text formats.

The release:

News Release – heic0814: Lenses galore – Hubble finds large sample of very distant galaxies

 
 24-Jul-2008: New Hubble Space Telescope observations of six spectacular galaxy clusters acting as gravitational lenses have given significant insights into the early stages of the Universe. Scientists have found the largest sample of very distant galaxies seen to date: ten promising candidates thought to lie at a distance of 13 billion light-years (~redshift 7.5). 

By using the gravitational magnification from six massive lensing galaxy clusters, the NASA/ESA Hubble Space Telescope has provided scientists with the largest sample of very distant galaxies seen to date. Some of the newly found magnified objects are dimmer than the faintest ones seen in the legendary Hubble Ultra Deep Field, which is usually considered the deepest image of the Universe.

By combining both visible and near-infrared observations from Hubble’s Advanced Camera for Surveys (ACS) and Near Infrared Camera and Multi-Object Spectrometer (NICMOS), scientists searched for galaxies that are only visible in near-infrared light. They uncovered 10 candidates believed to lie about 13 billion light-years away (a redshift of approximately 7.5), which means that the light gathered was emitted by the stars when the Universe was still very young — a mere 700 million years old.

These candidates could well explain one of the big puzzles plaguing astronomy today. We know that the Universe was reionised within the first 5-600 million years after the Big Bang, but we don’t know if the ionising energy came from a smaller number of big galaxies or a more plentiful population of tiny ones”, said Johan Richard, from the California Institute of Technology. The relatively high number of redshift 7.5 galaxies claimed in this survey suggests that most of the ionising energy was produced by dim and abundant galaxies rather than large, scarce ones.

The challenge for astronomers is that galaxies beyond a distance of 13 billion light-years (past a redshift of 7) are exceedingly faint and are only visible in the near-infrared — just at the limit of what Hubble can observe” explained Jean-Paul Kneib from the Laboratoire d’astrophysique de Marseille. This new result was only made possible with some cosmic assistance in the form of gravitational lensing that magnified the light from the distant galaxies enough for Hubble to detect them. A firm confirmation of their distance was beyond even the capabilities of the 10-meter Keck telescope and must await powerful future ground-based telescopes.

First confirmed in 1979, gravitational lenses were predicted by Albert Einstein’s theory of General Relativity, a theory that allows astronomers to calculate the path of starlight as it moves through curved space-time. According to the theory, the bending of light is brought about by the presence of matter in the Universe, which causes the fabric of space-time to warp and curve.

Gravitational lensing is the result of this warping of spacetime and is mainly detected around very massive galaxy clusters. Due to the gravitational effect of both the cluster’s observable matter and hidden dark matter, the light is bent around the cluster. This bending of light allows the clusters in certain places to act as natural gravitational telescopes that give the light of faint and faraway objects a boost.

Where Earth-bound telescopes fail to detect such faint and distant objects due to the blurring introduced by the Earth’s atmosphere, a combination of Hubble’s location in space and the magnification of the gravitation lenses provides astronomers with a birds-eye view of these elusive objects.

This technique has already been used numerous times by Hubble and has helped astronomers to find and study many of the most distant known galaxies.

 

Notes for editors:

 

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

Image credit: NASA, ESA and Johan Richard (Caltech, USA)
Acknowledgement: Davide de Martin & James Long (ESA/Hubble)

 

Links:

Wikipedia site explaining Gravitational Lensing
More Hubble discoveries relating to gravitational lenses