A new study claims that the Milky Way is home to billions of planets positioned at the ‘habitable zone.’
According to the new study based on 151 multi-planetary systems found by NASA’s Kepler space telescope, a lot more planets than thought before are at the right distance for liquid surface water, which is necessary to harbor life.
Multiple Planets in the Habitable Zone. Credit PHL @ UPR Arecibo, NASA.
Steffen Kjær Jacobsen, co-author of the study published in the Monthly Notices of the Royal Astronomical Society journal, said:
“We decided to use this method to calculate the potential planetary positions in 151 planetary systems, where the Kepler satellite had found between three and six planets…But we only made calculations for planets where there is a good chance that you can see them with the Kepler satellite.”
If there are billions of habitable planets in the Milky Way, can you imagine how many exist in the Universe that holds billions of Galaxies!
The Habitable Zone. Credit PHL @ UPR Arecibo, NASA.
Kepler-11, a star system crammed with 6 exoplanets — its existence defies conventional planet-forming wisdom. Credit NASA/Tim Pyle.
via discovery, wordlesstech
What does the magnetic field of our Galaxy look like?
It has long been known that a modest magnetic field pervades our Milky Way Galaxy because it is seen to align small dust grains that scatter background light. Only recently, however, has the Sun-orbiting Planck satellite made a high-resolution map of this field. Color coded, the 30-degree wide map confirms, among other things, that the Galaxy’s interstellar magnetism is strongest in the central disk.
The revolution of charged gas around the Galactic center creates this magnetism, and it is hypothesized that viewed from the top, the Milky Way’s magnetic field would appear as a spiral swirling out from the center. What caused many of the details in this and similar Planck maps — and how magnetism in general affected our Galaxy’s evolution — will likely remain topics of research for years to come.
Image Credit & Copyright: ESA/Planck; Acknowledgement: M.-A. Miville-Deschênes, CNRS – IAS, U. Paris-XI
This is a nighttime view of the current sky, with the bright belt of our Milky Way. The Andromeda galaxy lies 2.5 million light-years away and looks like a faint spindle, several times the diameter of the full Moon.
NASA astronomers say they can now predict with certainty the next major cosmic event to affect our galaxy, sun, and solar system: the titanic collision of our Milky Way galaxy with the neighboring Andromeda galaxy.
The Milky Way is destined to get a major makeover during the encounter, which is predicted to happen four billion years from now. It is likely the sun will be flung into a new region of our galaxy, but our Earth and solar system are in no danger of being destroyed.
“After nearly a century of speculation about the future destiny of Andromeda and our Milky Way, we at last have a clear picture of how events will unfold over the coming billions of years,” says Sangmo Tony Sohn of the Space Telescope Science Institute (STScI) in Baltimore.
“Our findings are statistically consistent with a head-on collision between the Andromeda galaxy and our Milky Way galaxy,” adds Roeland van der Marel of the STScI.
2 Billion Years: The disk of the approaching Andromeda galaxy is noticeably larger.
3.75 Billion Years: Andromeda fills the field of view. The Milky Way begins to show distortion due to tidal pull from Andromeda.
3.85-3.9 Billion Years: During the first close approach, the sky is ablaze with new star formation, which is evident in a plethora of emission nebulae and open young star clusters.
3.85-3.9 Billion Years
4 Billion Years: After its first close pass, Andromeda is tidally stretched out. The Milky Way, too, becomes warped.
5.1 Billion Years: During the second close passage, the cores of the Milky Way and Andromeda appear as a pair of bright lobes. Star-forming nebulae are much less prominent because the interstellar gas and dust has been significantly decreased by previous bursts of star formation.
7 Billion Years: The merged galaxies form a huge elliptical galaxy, its bright core dominating the nighttime sky. Scoured of dust and gas, the newly merged elliptical galaxy no longer makes stars and no nebulae appear in the sky. The aging starry population is no longer concentrated along a plane, but instead fills an ellipsoidal volume.
The solution came through painstaking NASA Hubble Space Telescope measurements of the motion of Andromeda, which also is known as M31. The galaxy is now 2.5 million light-years away, but it is inexorably falling toward the Milky Way under the mutual pull of gravity between the two galaxies and the invisible dark matter that surrounds them both.
The scenario is like a baseball batter watching an oncoming fastball. Although Andromeda is approaching us more than 2,000 times faster than a fastball, it will take 4 billion years before the strike. Computer simulations derived from Hubble’s data show that it will take an additional two billion years after the encounter for the interacting galaxies to completely merge under the tug of gravity and reshape into a single elliptical galaxy similar to the kind commonly seen in the local universe.
Although the galaxies will plow into each other, stars inside each galaxy are so far apart that they will not collide with other stars during the encounter. However, the stars will be thrown into different orbits around the new galactic center. Simulations show that our solar system will probably be tossed much farther from the galactic core than it is today.
To make matters more complicated, M31’s small companion, the Triangulum galaxy, M33, will join in the collision and perhaps later merge with the M31/Milky Way pair. There is a small chance that M33 will hit the Milky Way first.
A century ago astronomers did not realize that M31 was a separate galaxy far beyond the stars of the Milky Way. Edwin Hubble measured its vast distance by uncovering a variable star that served as a “milepost marker.”
Hubble went on to discover the expanding universe where galaxies are rushing away from us, but it has long been known that M31 is moving toward the Milky Way at about 250,000 miles per hour. That is fast enough to travel from here to the moon in one hour. The measurement was made using the Doppler effect, which is a change in frequency and wavelength of waves produced by a moving source relative to an observer, to measure how starlight in the galaxy has been compressed by Andromeda’s motion toward us.
Previously, it was unknown whether the far-future encounter will be a miss, glancing blow, or head-on smashup. This depends on M31’s tangential motion. Until now, astronomers had not been able to measure M31’s sideways motion in the sky, despite attempts dating back more than a century. The Hubble Space Telescope team, led by van der Marel, conducted extraordinarily precise observations of the sideways motion of M31 that remove any doubt that it is destined to collide and merge with the Milky Way.
“This was accomplished by repeatedly observing select regions of the galaxy over a five- to seven-year period,” says Jay Anderson of STScI.
“In the worst-case-scenario simulation, M31 slams into the Milky Way head-on and the stars are all scattered into different orbits,” adds Gurtina Besla of Columbia University in New York, N.Y. “The stellar populations of both galaxies are jostled, and the Milky Way loses its flattened pancake shape with most of the stars on nearly circular orbits. The galaxies’ cores merge, and the stars settle into randomized orbits to create an elliptical-shaped galaxy.”
The space shuttle servicing missions to Hubble upgraded it with ever more-powerful cameras, which have given astronomers a long-enough time baseline to make the critical measurements needed to nail down M31’s motion. The Hubble observations and the consequences of the merger are reported in three papers that will appear in an upcoming issue of the Astrophysical Journal.
Images © ESA- Planck, Marc-Antoine Miville-Deschenes
The impressive shape of our Galaxy’s (Milky Way) magnetic field and its temperature, captured by the Planck spacecraft.
The European Space Agency explains: Colors draw the thermal emission of dust while the reliefs draw the galactic magnetic field.
The colors show temperature, with dark red the hottest and dark blue the coldest.
Source European Space Agency via Worldlesstech
26 November 2012
The Milky Way Galaxy, above Paranal Laboratory.Credit: European Southern Observatory
Just after the Big Bang, scientists theorise the Universe was equal parts matter and its opposite, but now, antimatter is almost non-existent. Astronomer-detectives are on the case.
Federation Fellow of The University of Sydney’s School of Physics, and Senior Fellow at Merton College, Oxford, Professor Joss Bland-Hawthorn will delve into the mysteries of antimatter at the final Monash Centre for Astrophysics (MoCA) public lecture for 2012, to be held this week.
The free talks, hosted regularly by MoCA, feature top astrophysics researchers who explain the mysteries of space to interested members of the public. Audience members are encouraged to ask questions following the talks.
First discovered in the 1930s, antimatter remains cryptic, with scientists still working to understand exactly what it is, and where most of it disappeared to after the creation of the universe.
What is known, is that antiparticles have the opposite charge and quantum spin to matter particles. When matter and antimatter combine, both are annihilated and converted into pure energy.
MoCA researcher Dr Samantha Penny said the asymmetry of matter and antimatter was one of the great unsolved problems of modern physics.
“The 80-year old mystery of antimatter recently became more complex when the astronomers observed evidence of the annihilation of antimatter emanating from the centre of our galaxy,” Dr Penny said.
“This exciting discovery means that antimatter does still exist in space, and is in fact, being destroyed at the astonishing rate of 16 billion tonnes every second.”
Professor Bland-Hawthorn will discuss the creation, existence and unknowns of antimatter the MoCA lecture.
“It’s not completely gone, but what is it doing there?” Professor Bland Hawthorn said.
“There is a massive black hole four million times the mass of the sun in the centre of our galaxy. Is it somehow related to that?”
Professor Joss Bland-Hawthorn will deliver ‘Nemesis: the search for antimatter in the Universe’ at 6.30pm, Thursday November 29 in Lecture Theatre S3, Monash University Clayton campus.
No registration is necessary. More information is available from the MoCA website.
Editors note: Full article can be found here.