Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Magnetic ‘Force Field’ Shields Giant Gas Cloud during Collision with Milky Way

01.11.2013
Doom may be averted for the Smith Cloud, a gigantic streamer of hydrogen gas that is on a collision course with the Milky Way Galaxy.

Astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) and Robert C. Byrd Green Bank Telescope (GBT) have discovered a magnetic field deep in the cloud’s interior, which may protect it during its meteoric plunge into the disk of our Galaxy.

This discovery could help explain how so-called high velocity clouds (HVCs) remain mostly intact during their mergers with the disks of galaxies, where they would provide fresh fuel for a new generation of stars.

Currently, the Smith Cloud is hurtling toward the Milky Way at more than 150 miles per second and is predicted to impact in approximately 30 million years. When it does, astronomers believe, it will set off a spectacular burst of star formation. But first, it has to survive careening through the halo, or atmosphere, of hot ionized gas surrounding the Milky Way.

“The million-degree upper atmosphere of the Galaxy ought to destroy these hydrogen clouds before they ever reach the disk, where most stars are formed,” said Alex Hill, an astronomer at Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO) and lead author of a paper published in the Astrophysical Journal. “New observations reveal one of these clouds in the process of being shredded, but a protective magnetic field shields the cloud and may help it survive its plunge.”

Many hundreds of HVCs zip around our Galaxy, but their obits seldom correspond to the rotation of the Milky Way. This leads astronomers to believe that HVCs are the left-over building blocks of galaxy formation or the splattered remains of a close galactic encounter billions of years ago.

Though massive, the gas that makes up HVCs is very tenuous, and computer simulations predict that they lack the necessary heft to survive plunging through the halo and into the disk of the Milky Way.

“We have long had trouble understanding how HVCs reach the Galactic disk,” said Hill. “There's good reason to believe that magnetic fields can prevent their ‘burning up’ in the halo like a meteorite burning up in Earth’s atmosphere.”

Despite being the best evidence yet for a magnetic field inside an HVC, the origin of the Smith Cloud’s field remains a mystery. “The field we observe now is too large to have existed in its current state when the cloud was formed,” said Hill. “The field was probably magnified by the cloud's motion through the halo.”

Earlier research indicates the Smith Cloud has already survived punching through the disk of our Galaxy once and -- at about 8,000 light-years from the disk -- is just beginning its re-entry now.

“The Smith Cloud is unique among high-velocity clouds because it is so clearly interacting with and merging with the Milky Way,” said Felix J. Lockman, an astronomer at the National Radio Astronomy Observatory (NRAO) in Green Bank, W.Va. “Its comet-like appearance indicates it’s already feeling the Milky Way’s influence.”

Since the Smith Cloud appears to be devoid of stars, the only way to observe it is with exquisitely sensitive radio telescopes, like the GBT, which can detect the faint emission of neutral hydrogen. If it were visible with the naked eye, the Smith Cloud would cover almost as much sky as the constellation Orion.

When the Smith Cloud eventually merges with the Milky Way, it could produce a bright ring of stars similar to the one relatively close to our Sun known as Gould's Belt.

“Our Galaxy is in an incredibly dynamic environment,” concludes Hill, “and how it interacts with that environment determines whether stars like the Sun will continue to form.”

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Alex S. Hill, S. A. Mao, Robert A. Benjamin, Felix J. Lockman and Naomi M. McClure-Griffiths. “Magnetized Gas in the Smith High Velocity Cloud”. The Astrophysical Journal, Volume 777, Issue 1, p. 55 (2013). doi:10.1088/0004-637X/777/1/55 Also online at http://arxiv.org/abs/1309.2553v2.

Charles Blue | EurekAlert!
Further information:
http://www.nrao.edu

More articles from Physics and Astronomy:

nachricht Breaking the optical bandwidth record of stable pulsed lasers
24.01.2017 | Institut national de la recherche scientifique - INRS

nachricht European XFEL prepares for user operation: Researchers can hand in first proposals for experiments
24.01.2017 | European XFEL GmbH

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists spin artificial silk from whey protein

X-ray study throws light on key process for production

A Swedish-German team of researchers has cleared up a key process for the artificial production of silk. With the help of the intense X-rays from DESY's...

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Breaking the optical bandwidth record of stable pulsed lasers

24.01.2017 | Physics and Astronomy

Choreographing the microRNA-target dance

24.01.2017 | Life Sciences

Spanish scientists create a 3-D bioprinter to print human skin

24.01.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>