Source: ESA
A crustacean from the Alpioniscus species.
Image credits: ESA–M. Fincke.
It is not every day that astronauts can claim to return to Earth with a new species of life. But when the astronauts on ESA’s CAVES underground training course returned to the surface they were carrying a special type of woodlouse. (read more)
Source: ESO Science Release eso1246
Artist’s impression of the surface of the dwarf planet Makemake .
Image credits: ESO/L. Calçada/Nick Risinger (skysurvey.org)
Astronomers have used three telescopes at ESO’s observatories in Chile to observe the dwarf planet Makemake as it drifted in front of a distant star and blocked its light. The new observations have allowed them to check for the first time whether Makemake is surrounded by an atmosphere. This chilly world has an orbit lying in the outer Solar System and was expected to have an atmosphere like Pluto (eso0908), but this is now shown not to be the case. The scientists also measured Makemake’s density for the first time. The new results are to be published in the 22 November issue of the journal Nature. (read more)
Source: ESA
Galaxy clusters connected by gas bridge.
Image credits: Sunyaev–Zel’dovich effect: ESA Planck Collaboration;
optical image: STScI Digitized Sky Survey
ESA’s Planck space telescope has made the first conclusive detection of a bridge of hot gas connecting a pair of galaxy clusters across 10 million light-years of intergalactic space.(read more)
Source: ESA
The Hubble Tuning Fork
Image credits: C. North, M. Galametz & the Kingfish Team
Galaxies come in all shapes and sizes: from those with compact fuzzy bulges or central bars to galaxies with winding spiral arms. Astronomer Edwin Hubble classified these different breeds of galaxies by means of a diagram known as the Hubble Tuning Fork.
The tuning fork shape presents elliptical galaxies along the handle, and two different populations of spiral galaxies on the fork’s ‘prongs’ to differentiate between spiral galaxies with a central bar, and those without.
The diagram also describes the shape of the galaxies. Elliptical galaxies are positioned further along the handle towards the fork depending on how elongated they appear, while spiral galaxies are organised by how tightly wound their arms are.
Of course, there are always exceptions, and a separate class of ‘irregular’ galaxies conforms to neither group, perhaps as a result of a collision or merging event disrupting their shape.
In this interactive tuning fork diagram, 61 nearby galaxies studied by ESA’s Herschel and NASA’s Spitzer space telescopes are presented. The galaxies are located 10–100 million light-years from Earth and were surveyed as part of two programmes: the Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel (Kingfish) and the Spitzer Infrared Nearby Galaxies Survey (Sings).
Rather than stars, the images show dust between them that is gently heated by hot young stars, visible only to heat-seeking infrared telescopes such as Herschel and Spitzer.
Each individual image is a three-color composite showing warm dust (blue) detected by Spitzer at 24 microns, and cooler dust traced by Herschel at 100 microns (green) and 250 microns (red).
By clicking on each of the galaxies, more information is provided about their classification, distance, size and location in the sky.
The galaxies were chosen to cover a wide range of characteristics to improve our understanding of the processes linking star formation to the local interstellar environment in the nearby Universe.
Source: ESA
Abell 30: a born-again planetary nebula.
Image credits: Main image: X-ray: ESA/XMM-Newton;
optical: NSF/NOAO/KPNO; inset: NASA/CXC/IAA-CSIC/M. Guerrero et al;
optical: NASA/STScI
Astronomers have found evidence for a dying Sun-like star coming briefly back to life after casting its gassy shells out into space, mimicking the possible fate our own Solar System faces in a few billion years. (read more)
Source: ESA/Hubble heic1217
Hubble spots candidate for most distant known galaxy.
Image credits: NASA, ESA, and M. Postman and D. Coe (Space Telescope Science Institute), and the CLASH team.
By combining the power of the NASA/ESA Hubble Space Telescope, NASA’s Spitzer Space Telescope and one of nature’s zoom lenses, astronomers have found what is probably the most distant galaxy yet seen in the Universe. The object offers a peek back into a time when the Universe was only 3 percent of its present age of 13.7 billion years.(read more)
Source: MESSENGER
Image credits: MESSENGER
MESSENGER has discovered assemblages of tectonic landforms unlike any previously found on Mercury or elsewhere in the Solar System. The findings are reported in a paper led by Smithsonian scientist Thomas Watters, “Extension and contraction within volcanically buried impact craters and basins on Mercury,” published in the December issue of the journal Geology and available online at http://geology.gsapubs.org/
The surface of Mercury is covered with deformational landforms that formed by faulting in response to horizontal contraction or shortening as the planet’s interior cooled and surface area shrank, causing blocks of crustal material to be pushed together. Contraction from cooling of Mercury’s interior has been so dominant that extensional landforms caused by fault formation in response to horizontal stretching and pulling apart of crustal material had not been previously documented outside of the interiors of a few large impact basins.
The MESSENGER spacecraft, in orbit around Mercury since March of last year, has revealed families of extensional troughs, or graben, that are encircled by contractional wrinkle ridges arranged in circular rings. The troughs can form complex patterns varying from the outlines of polygons inside the ridge rings to arcs that parallel the bounding ridges.
“The pattern of winkle ridges and graben resembles the raised edge and cracks in a pie crust,” said Watters of the Center for Earth and Planetary Studies at the National Air and Space Museum. The “pie crust” analogy also fits another notable aspect of these collections of tectonic landforms – their association with “ghost” craters. Ghost craters are impact craters that have been flooded and buried by lava flows. The thin volcanic deposits overlying the rim of a fully buried impact crater serve to concentrate contractional forces, leading to the formation of a ridge ring that reveals the outline of the buried crater.
“The special arrangement of the wrinkle ridges and graben in many of the ghost craters on Mercury is due to a combination of extensional forces from cooling and contraction of unusually thick lava flow units and contractional forces from cooling and contraction of the planet’s interior,” says Sean Solomon of the Columbia University’s Lamont-Doherty Earth Observatory, coauthor and principal investigator of the MESSENGER mission. The eruption and rapid accumulation of very fluid lava flows into thick cooling units on a planet undergoing a high rate of global contraction may be why these systems of tectonic landforms in ghost craters on Mercury have not been seen elsewhere in the Solar System.
Source: NASA
NASA is marking two milestones in the search for planets like Earth; the successful completion of the Kepler Space Telescope's 3 1/2- year prime mission and the beginning of an extended mission that could last as long as four years.
Scientists have used Kepler data to identify more than 2,300 planet candidates and confirm more than 100 planets. Kepler is teaching us the galaxy is teeming with planetary systems and planets are prolific, and giving us hints that nature makes small planets efficiently.
So far, hundreds of Earth-size planet candidates have been found as well as candidates that orbit in the habitable zone, the region in a planetary system where liquid water might exist on the surface of a planet. None of the candidates is exactly like Earth. With the completion of the prime mission, Kepler now has collected enough data to begin finding true sun-Earth analogs -- Earth-size planets with a one-year orbit around stars similar to the sun. (read more)
Source: ESA
The total solar eclipse of 13/14 November 2012.
Image credits: Anik De Groof.
ESA’s Sun-watching Proba-2 satellite experienced three partial solar eclipses last night while lucky observers watching from northern Australia were treated to a total solar eclipse.
During a total solar eclipse, the Moon moves in front of the Sun as seen from Earth, their alignment and separation such that the much closer Moon appears large enough to block out the light from the much more distant Sun.
Since Proba-2 orbits Earth about 14.5 times per day, it can dip in and out of the Moon’s shadow around the time of a solar eclipse. The constant change in viewing angle of Proba-2 meant that the satellite passed through the shadow three times during the eclipse yesterday, as shown in the video presented here.
As the Sun was never completely covered up from Proba-2’s vantage point, each eclipse was only partial. (read more)
Source: ESO Science Release 1245
Artist’s impression of the free-floating planet CFBDSIR J214947.2-040308.9.
Image credits: ESO/L. Calçada/P. Delorme/R. Saito/VVV Consortium
Astronomers using ESO’s Very Large Telescope and the Canada-France-Hawaii Telescope have identified a body that is very probably a planet wandering through space without a parent star. This is the most exciting free-floating planet candidate so far and the closest such object to the Solar System at a distance of about 100 light-years. Its comparative proximity, and the absence of a bright star very close to it, has allowed the team to study its atmosphere in great detail. This object also gives astronomers a preview of the exoplanets that future instruments aim to image around stars other than the Sun. (read more)
Source: NASA Press Release 12-387
The Five Most Abundant Gases in the Martian
Atmosphere measured by SAM in October 2012.
Image credits: NASA/JPL-Caltech, SAM/GSFC.
NASA's car-sized rover, Curiosity, has taken significant steps toward understanding how Mars may have lost much of its original atmosphere.
Learning what happened to the Martian atmosphere will help scientists assess whether the planet ever was habitable. The present atmosphere of Mars is 100 times thinner than Earth's.
A set of instruments aboard the rover has ingested and analyzed samples of the atmosphere collected near the "Rocknest" site in Gale Crater where the rover is stopped for research. Findings from the Sample Analysis at Mars (SAM) instruments suggest that loss of a fraction of the atmosphere, resulting from a physical process favoring retention of heavier isotopes of certain elements, has been a significant factor in the evolution of the planet. Isotopes are variants of the same element with different atomic weights.
Initial SAM results show an increase of 5 percent in heavier isotopes of carbon in the atmospheric carbon dioxide compared to estimates of the isotopic ratios present when Mars formed. These enriched ratios of heavier isotopes to lighter ones suggest the top of the atmosphere may have been lost to interplanetary space. Losses at the top of the atmosphere would deplete lighter isotopes. Isotopes of argon also show enrichment of the heavy isotope, matching previous estimates of atmosphere composition derived from studies of Martian meteorites on Earth.
Scientists theorize that in Mars' distant past its environment may have been quite different, with persistent water and a thicker atmosphere. NASA's Mars Atmosphere and Volatile Evolution, or MAVEN, mission will investigate possible losses from the upper atmosphere when it arrives at Mars in 2014.
With these initial sniffs of Martian atmosphere, SAM also made the most sensitive measurements ever to search for methane gas on Mars. Preliminary results reveal little to no methane. Methane is of interest as a simple precursor chemical for life. On Earth, it can be produced by either biological or non-biological processes.
Methane has been difficult to detect from Earth or the current generation of Mars orbiters because the gas exists on Mars only in traces, if at all. The Tunable Laser Spectrometer (TLS) in SAM provides the first search conducted within the Martian atmosphere for this molecule. The initial SAM measurements place an upper limit of just a few parts methane per billion parts of Martian atmosphere, by volume, with enough uncertainty that the amount could be zero.
"Methane is clearly not an abundant gas at the Gale Crater site, if it is there at all. At this point in the mission we're just excited to be searching for it," said SAM TLS lead Chris Webster of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "While we determine upper limits on low values, atmospheric variability in the Martian atmosphere could yet hold surprises for us."
In Curiosity's first three months on Mars, SAM has analyzed atmosphere samples with two laboratory methods. One is a mass spectrometer investigating the full range of atmospheric gases. The other, TLS, has focused on carbon dioxide and methane. During its two-year prime mission, the rover also will use an instrument called a gas chromatograph that separates and identifies gases. The instrument also will analyze samples of soil and rock, as well as more atmosphere samples.
"With these first atmospheric measurements we already can see the power of having a complex chemical laboratory like SAM on the surface of Mars," said SAM Principal Investigator Paul Mahaffy of NASA's Goddard Space Flight Center in Greenbelt, Md. "Both atmospheric and solid sample analyses are crucial for understanding Mars' habitability."
SAM is set to analyze its first solid sample in the coming weeks, beginning the search for organic compounds in the rocks and soils of Gale Crater. Analyzing water-bearing minerals and searching for and analyzing carbonates are high priorities for upcoming SAM solid sample analyses.
Source: ESO Photo Release eso1243
The globular star cluster NGC 6362.
Image credit: ESO.
This colourful view of the globular star cluster NGC 6362 was captured by the Wide Field Imager attached to the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. This new picture, along with a new image of the central region from the NASA/ESA Hubble Space Telescope, provide the best view of this little-known cluster ever obtained. Globular clusters are mainly composed of tens of thousands of very ancient stars, but they also contain some stars that look suspiciously young. (read more)
