Sharp images obtained by the Hubble Space Telescope confirm that three supernovae discovered several years ago exploded in the dark emptiness of intergalactic space, having been flung from their home galaxies millions or billions of years earlier.
Most supernovae are found inside galaxies containing hundreds of billions of stars, one of which might explode per century per galaxy.
These lonely supernovae, however, were found between galaxies in three large clusters of several thousand galaxies each. The stars’ nearest neighbors were probably 300 light years away, nearly 100 times farther than our sun’s nearest stellar neighbor, Proxima Centauri, 4.24 light years distant.
uch rare solitary supernovae provide an important clue to what exists in the vast empty spaces between galaxies, and can help astronomers understand how galaxy clusters formed and evolved throughout the history of the universe.
When you’re blasting though space at more than 98 percent of the speed of light, you may need driver’s insurance. Astronomers have discovered for the first time a rear-end collision between two high-speed knots of ejected matter from a super-massive black hole. This discovery was made while piecing together a time-lapse movie of a plasma jet blasted from a supermassive black hole inside a galaxy located 260 million light-years from Earth.
he finding offers new insights into the behavior of “light-saber-like” jets that are so energized that they appear to zoom out of black holes at speeds several times the speed of light. This “superluminal” motion is an optical illusion due to the very fast real speed of the plasma, which is close to the universal maximum of the speed of light.
Such extragalactic jets are not well understood. They appear to transport energetic plasma in a confined beam from the central black hole of the host galaxy. The new analysis suggests that shocks produced by collisions within the jet further accelerate particles and brighten the regions of colliding material.
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If you lived on one of Pluto’s moons Nix or Hydra, you’d have a hard time setting your alarm clock. That’s because you could not know for sure when, or even in which direction, the sun would rise.
A comprehensive analysis of all available Hubble Space Telescope data shows that two of Pluto’s moons, Nix and Hydra, are wobbling unpredictably. Scientists believe the other two small moons, Kerberos and Styx, are likely in a similar situation, pending further study.
“Hubble has provided a new view of Pluto and its moons revealing a cosmic dance with a chaotic rhythm,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate in Washington, D.C. “When the New Horizons spacecraft flies through the Pluto system in July we’ll get a chance to see what these moons look like up close and personal.”
Why the chaos? Because the moons are embedded inside a dynamically shifting gravitational field caused by the system’s two central bodies, Pluto and Charon, whirling about each other. The variable gravitational field induces torques that send the smaller moons tumbling in unpredictable ways. This torque is strengthened by the fact the moons are football shaped rather than spherical.
NASA has selected nine science instruments for a mission to Jupiter’s moon Europa, to investigate whether the mysterious icy moon could harbor conditions suitable for life.
NASA’s Galileo mission yielded strong evidence that Europa, about the size of Earth’s moon, has an ocean beneath a frozen crust of unknown thickness. If proven to exist, this global ocean could have more than twice as much water as Earth. With abundant salt water, a rocky sea floor, and the energy and chemistry provided by tidal heating, Europa could be the best place in the solar system to look for present day life beyond our home planet.
“Europa has tantalized us with its enigmatic icy surface and evidence of a vast ocean, following the amazing data from 11 flybys of the Galileo spacecraft over a decade ago and recent Hubble observations suggesting plumes of water shooting out from the moon,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington. “We’re excited about the potential of this new mission and these instruments to unravel the mysteries of Europa in our quest to find evidence of life beyond Earth.”
Astronomers using NASA’s Hubble Space Telescope have uncovered surprising new clues about a hefty, rapidly aging star whose behavior has never been seen before in our Milky Way galaxy. In fact, the star is so weird that astronomers have nicknamed it “Nasty 1,” a play on its catalog name of NaSt1. The star may represent a brief transitory stage in the evolution of extremely massive stars.
First discovered several decades ago, Nasty 1 was identified as a Wolf-Rayet star, a rapidly evolving star that is much more massive than our sun. The star loses its hydrogen-filled outer layers quickly, exposing its super-hot and extremely bright helium-burning core.
But Nasty 1 doesn’t look like a typical Wolf-Rayet star. The astronomers using Hubble had expected to see twin lobes of gas flowing from opposite sides of the star, perhaps similar to those emanating from the massive star Eta Carinae, which is a Wolf-Rayet candidate. Instead, Hubble revealed a pancake-shaped disk of gas encircling the star. The vast disk is nearly 2 trillion miles wide, and may have formed from an unseen companion star that snacked on the outer envelope of the newly formed Wolf-Rayet. Based on current estimates, the nebula surrounding the stars is just a few thousand years old, and as close as 3,000 light-years from Earth.
As part of an observing program carried out with the Subaru Telescope and the Hubble Space Telescope, a group of researchers from the “Service d’Astrophysique-Laboratoire AIM” of CEA-IRFU led by Anita Zanella discovered the birth cry of a massive star-forming clump in the disk of a very distant galaxy. This giant clump is less than 10 million years old, and it is the very first time that such a young star-forming region is observed in the distant Universe. This discovery sheds new light on how stars were born within distant galaxies. The physical properties of this object reveal that newly-born clumps in such galaxies survive from stellar winds and supernovae feedback, and can thus live for a few hundred million years unlike the predictions from several theoretical models. Their long lifetime could enable their migration toward the inner regions of the galaxy, hence contributing to the total mass of the galactic bulge and the growth of the central black hole. These results are published in the “Nature” journal from May 2015.
Using NASA’s Hubble Space Telescope, astronomers have captured for the first time snapshots of fledging white dwarf stars beginning their slow-paced, 40-million-year migration from the crowded center of an ancient star cluster to the less populated suburbs.
White dwarfs are the burned-out relics of stars that rapidly lose mass, cool down and shut off their nuclear furnaces. As these glowing carcasses age and shed weight, their orbits begin to expand outward from the star cluster’s packed downtown. This migration is caused by a gravitational tussle among stars inside the cluster. Globular star clusters sort out stars according to their mass, governed by a gravitational billiard ball game where lower mass stars rob momentum from more massive stars. The result is that heavier stars slow down and sink to the cluster’s core, while lighter stars pick up speed and move across the cluster to the edge. This process is known as “mass segregation.” Until these Hubble observations, astronomers had never definitively seen the dynamical conveyor belt in action.
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