Hubble and Chandra Discover Dark Matter Is Not as Sticky as Once Thought
Thu, 26 Mar 2015 14:00:00 -0400
In particle physics labs, like the Large Hadron Collider in Geneva, Switzerland,
scientists smash atoms together to study the underpinnings of matter and energy.
On the scale of the macrocosm, nature provides a similar experiment by crashing
clusters of galaxies together. Besides galaxies and gas, the galaxy clusters
contain huge amounts of dark matter. Dark matter is a transparent form of matter
that makes up most of the mass in the universe. During collisions, the clouds of
gas enveloping the galaxies crash into each other and slow down or stop.
Astronomers found that the dark matter continued straight through the violent
collisions, without slowing down relative to the galaxies. Their best explanation
is that the dark matter did not interact with visible particles, and it also
interacted less frequently with other dark matter than previously thought.
Astronomers used the Hubble Space Telescope and Chandra X-ray Observatory to study
72 large galaxy cluster collisions. Chandra traced the hot gas, and Hubble saw
how the invisible dark matter warps space and distorts the images of background
stars. This allowed for the distribution of dark matter in the collision to be
mapped. The finding narrows down the options for what this dark matter might be.
Hubble Source Catalog: One-Stop Shopping for Astronomers
Fri, 13 Mar 2015 13:00:00 -0400
Astronomers at the Space Telescope Science Institute and the Johns Hopkins
University, both in Baltimore, Maryland, have created a new master catalog of
astronomical objects called the Hubble Source Catalog. The catalog provides one-stop
shopping for measurements of objects observed with NASA's Hubble Space Telescope.
NASA's Hubble Observations Suggest Underground Ocean on Jupiter's Largest Moon
Thu, 12 Mar 2015 11:00:00 -0400
Nearly 500 million miles from the Sun lies a moon orbiting Jupiter that is slightly
larger than the planet Mercury and may contain more water than all of Earth's
oceans. Temperatures are so cold, though, that water on the surface freezes as
hard as rock and the ocean lies roughly 100 miles below the crust. Nevertheless,
where there is water there could be life as we know it. Identifying liquid water on
other worlds big or small is crucial in the search for habitable planets beyond
Earth. Though the presence of an ocean on Ganymede has been long predicted
based on theoretical models, NASA's Hubble Space Telescope found the best evidence for it. Hubble was used to watch aurorae glowing above
the moon's icy surface. The aurorae are tied to the moon's magnetic field, which
descends right down to the core of Ganymede. A saline ocean would influence
the dynamics of the magnetic field as it interacts with Jupiter's own immense
magnetic field, which engulfs Ganymede. Because telescopes can't look inside
planets or moons, tracing the magnetic field through aurorae is a unique way to
probe the interior of another world.
Hubble Sees Supernova Split into Four Images by Cosmic Lens
Thu, 05 Mar 2015 14:00:00 -0500
Three-leaf clover plants abound everywhere: on lawns, in gardens, and in forests. But
spotting a four-leaf clover is a rare, lucky find. Astronomers using the Hubble Space
Telescope have found the equivalent of a four-leaf clover with the discovery of four
images of the same supernova. The images are arranged around a giant foreground
elliptical galaxy embedded in a cluster of galaxies. The arrangement forms a
cross-shaped pattern called an Einstein Cross. The powerful gravity from both the elliptical galaxy and its galaxy cluster magnifies the
light from the supernova behind them in an effect called gravitational lensing. The
elliptical galaxy and its galaxy cluster, MACS J1149.6+2223, are 5 billion light-years
away from Earth. The supernova behind it is 9.3 billion light-years away.
Hubble Gets Best View of a Circumstellar Debris Disk Distorted by a Planet
Thu, 19 Feb 2015 14:00:00 -0500
Over a decade before planets were found orbiting normal stars, the astronomy
world was intrigued by the discovery of a vast, edge-on, pancake-flat disk of dust
and gas encircling the newborn star Beta Pictoris. It appeared to validate the
hypothesis by the German philosopher Immanuel Kant, 230 years ago, that our solar
system was born when planets condensed from nebular material in the plane of such
a disk. (This model was independently proposed by French scholar Pierre-Simon
Laplace in 1796.) Kant regarded the coplanar obits of the planets a fossil skeleton
of the long-ago disintegrated disk. Though nearly two dozen circumstellar debris
disks have been viewed by the Hubble Space Telescope to date, Beta Pictoris is the
first and best example of what a forming young planetary system looks like. That's
because it can be seen edge on, and it is the only disk to date where a planet has
also been imaged. Hubble has been used to intensively study the disk for the past two
decades and this latest picture when compared to previous observations shows
that the disk particles appear to smoothly revolve around the star like a majestic
carousel. Ground-based telescopes found a Jupiter-sized world embedded in the disk in
2009, and future observations may yield more planetary objects.
Mars hills hide icy past - Read more >
Thu, 19 Feb 2015 11:00:00 +0100
A complex network of isolated hills, ridges and small basins spanning 1400 km on Mars is thought to hide large quantities of water-ice.
Hubble Captures Rare Triple-Moon Conjunction
Thu, 05 Feb 2015 10:00:00 -0500
Firing off a string of snapshots like a sports photographer at a NASCAR race, NASA's
Hubble Space Telescope captured a rare look at three of Jupiter's largest moons
zipping across the banded face of the gas-giant planet: Europa, Callisto, and Io.
Jupiter's four largest moons can commonly be seen transiting the face of the giant
planet and casting shadows onto its cloud tops. However, seeing three moons transiting
the face of Jupiter at the same time is rare, occurring only once or twice a decade.
Missing from the sequence, taken on January 24, 2015, is the moon Ganymede that
was too far from Jupiter in angular separation to be part of the conjunction.
Planck: gravitational waves remain elusive - Read more >
Fri, 30 Jan 2015 18:00:00 +0100
Despite earlier reports of a possible detection, a joint analysis of data from ESA’s Planck satellite and the ground-based BICEP2 and Keck Array experiments has found no conclusive evidence of primordial gravitational waves.
Hubble Spies a Loopy Galaxy
Thu, 29 Jan 2015 10:00:00 -0500
At first glance, galaxy NGC 7714 resembles a partial golden ring from an amusement
park ride. This unusual structure is a river of Sun-like stars that has been pulled deep
into space by the gravitational tug of a bypassing galaxy (not seen in this Hubble Space
Telescope photo). Though the universe is full of such colliding galaxies that are
distorted in a gravitational taffy-pull, NGC 7714 is particularly striking for the seeming
fluidity of the stars along a vast arc. The near-collision between the galaxies happened
at least 100 million years ago.
Rosetta watches comet shed its dusty coat - Read more >
Mon, 26 Jan 2015 17:00:00 +0100
ESA’s Rosetta mission is providing unique insight into the life cycle of a comet’s dusty surface, watching 67P/Churyumov–Gerasimenko as it sheds the dusty coat it has accumulated over the past four years.
Getting to know Rosetta’s comet - Read more >
Thu, 22 Jan 2015 20:00:00 +0100
Rosetta is revealing its host comet as having a remarkable array of surface features and with many processes contributing to its activity, painting a complex picture of its evolution.
Mysteries in Nili Fossae - Read more >
Thu, 22 Jan 2015 11:26:00 +0100
These new images from the high-resolution stereo camera on ESA’s Mars Express show Nili Fossae, one of the most enticing regions on Mars. This ‘graben system’ lies northeast of the volcanic region of Syrtis Major on the northwestern edge of the large Isidis impact basin – and intriguing hints of methane have been seen here.
Beagle-2 lander found on Mars - Read more >
Fri, 16 Jan 2015 11:00:00 +0100
The UK-led Beagle-2 Mars lander, which hitched a ride on ESA’s Mars Express mission and was lost on Mars since 2003, has been found in images taken by a NASA orbiter at the Red Planet.
Hubble Goes High Def to Revisit the Iconic 'Pillars of Creation'
Mon, 05 Jan 2015 17:15:00 -0500
Although NASA's Hubble Space Telescope has taken many breathtaking images of the
universe, one snapshot stands out from the rest: the iconic view of the so-called "Pillars
of Creation." The jaw-dropping photo, taken in 1995, revealed never-before-seen details
of three giant columns of cold gas bathed in the scorching ultraviolet light from a
cluster of young, massive stars in a small region of the Eagle Nebula, or M16.
Hubble Discovers that Milky Way Core Drives Wind at 2 Million Miles Per Hour
Mon, 05 Jan 2015 17:15:00 -0500
At a time when our earliest human ancestors had recently mastered walking upright, the
heart of our Milky Way galaxy underwent a titanic eruption, driving gases and
other material outward at 2 million miles per hour. Now, at least 2 million years
later, astronomers are witnessing the aftermath of the explosion: billowing clouds
of gas towering about 30,000 light-years above and below the plane of our
Hubble's High-Definition Panoramic View of the Andromeda Galaxy
Mon, 05 Jan 2015 17:15:00 -0500
The largest NASA Hubble Space Telescope image ever assembled, this sweeping view of a portion of the Andromeda galaxy (M31) is the sharpest large
composite image ever taken of our galactic neighbor. Though the galaxy is
over 2 million light-years away, the Hubble telescope is powerful enough to resolve
individual stars in a 61,000-light-year-long section of the galaxy's pancake-shaped disk.
It's like photographing a beach and resolving individual grains of sand. And, there are
lots of stars in this sweeping view over 100 million, with some of them in thousands
of star clusters seen embedded in the disk. This ambitious photographic cartography of
the Andromeda galaxy represents a new benchmark for precision studies of large spiral
galaxies which dominate the universe's population of over 100 billion galaxies. Never before have astronomers been able to see individual stars over a major portion of an external spiral galaxy. Most of the stars in the universe live inside
such majestic star cities, and this is the first data that reveal populations of stars in
context to their home galaxy.
Origin of high-latitude auroras revealed - Read more >
Thu, 18 Dec 2014 20:00:00 +0100
Auroras are the most visible manifestation of the Sun’s effect on Earth, but many aspects of these spectacular displays are still poorly understood. Thanks to ESA’s Cluster and NASA’s Image satellites working together, a particular type of very high-latitude aurora has now been explained.
Flying over Becquerel - Read more >
Thu, 18 Dec 2014 14:00:00 +0100
This latest release from the camera on ESA’s Mars Express is a simulated flight over the Becquerel crater, showing large-scale deposits of sedimentary material.
Venus Express goes gently into the night - Read more >
Tue, 16 Dec 2014 18:30:00 +0100
ESA’s Venus Express has ended its eight-year mission after far exceeding its planned life. The spacecraft exhausted its propellant during a series of thruster burns to raise its orbit following the low-altitude aerobraking earlier this year.