Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


The Corrugated Galaxy—Milky Way May Be Much Larger Than Previously Estimated


Findings Led by Rensselaer Polytechnic Institute Researchers Published in the Astrophysical Journal

The Milky Way galaxy is at least 50 percent larger than is commonly estimated, according to new findings that reveal that the galactic disk is contoured into several concentric ripples. The research, conducted by an international team led by Rensselaer Polytechnic Institute Professor Heidi Jo Newberg, revisits astronomical data from the Sloan Digital Sky Survey which, in 2002, established the presence of a bulging ring of stars beyond the known plane of the Milky Way.

Rensselaer Polytechnic Institute

The density of light in the Milky Way reveals a "rippling" galactic disk.

“In essence, what we found is that the disk of the Milky Way isn’t just a disk of stars in a flat plane—it’s corrugated,” said Heidi Newberg, professor of physics, applied physics, and astronomy in the Rensselaer School of Science. “As it radiates outward from the sun, we see at least four ripples in the disk of the Milky Way. While we can only look at part of the galaxy with this data, we assume that this pattern is going to be found throughout the disk.”

Importantly, the findings show that the features previously identified as rings are actually part of the galactic disk, extending the known width of the Milky Way from 100,000 light years across to 150,000 light years, said Yan Xu, a scientist at the National Astronomical Observatories of China (which is part of the Chinese Academy of Science in Beijing), former visiting scientist at Rensselaer, and lead author of the paper.

“Going into the research, astronomers had observed that the number of Milky Way stars diminishes rapidly about 50,000 light years from the center of the galaxy, and then a ring of stars appears at about 60,000 light years from the center,” said Xu. “What we see now is that this apparent ring is actually a ripple in the disk. And it may well be that there are more ripples further out which we have not yet seen.”

The research, funded in part by the National Science Foundation and titled “Rings and Radial Waves in the Disk of the Milky Way,” was published today in the Astrophysical Journal. Newberg, Xu, and their collaborators used data from the Sloan Digital Sky Survey (SDSS) to show an oscillating asymmetry in the main sequence star counts on either side of the galactic plane, starting from the sun and looking outward from the galactic center. In other words, when we look outward from the sun, the mid-plane of the disk is perturbed up, then down, then up, and then down again.

“Extending our knowledge of our galaxy’s structure is fundamentally important,” said Glen Langston, NSF program manager. “The NSF is proud to support their effort to map the shape of our galaxy beyond previously unknown limits.”

The new research builds upon a 2002 finding in which Newberg established the existence of the “Monoceros Ring,” an “over-density” of stars at the outer edges of the galaxy that bulges above the galactic plane. At the time, Newberg noticed evidence of another over-density of stars, between the Monoceros Ring and the sun, but was unable to investigate further. With more data available from the SDSS, researchers recently returned to the mystery.

“I wanted to figure out what that other over-density was,” Newberg said. “These stars had previously been considered disk stars, but the stars don’t match the density distribution you would expect for disk stars, so I thought ‘well, maybe this could be another ring, or a highly disrupted dwarf galaxy.”

When they revisited the data, they found four anomalies: one north of the galactic plane at 2 kilo-parsecs (kpc) from the sun, one south of the plane at 4-6 kpc, a third to the north at 8-10 kpc, and evidence of a fourth to the south 12-16 kpc from the sun. The Monoceros Ring is associated with the third ripple. The researchers further found that the oscillations appear to line up with the locations of the galaxy’s spiral arms. Newberg said the findings support other recent research, including a theoretical finding that a dwarf galaxy or dark matter lump passing through the Milky Way would produce a similar rippling effect. In fact, the ripples might ultimately be used to measure the lumpiness of dark matter in our galaxy.

“It’s very similar to what would happen if you throw a pebble into still water – the waves will radiate out from the point of impact,” said Newberg. “If a dwarf galaxy goes through the disk, it would gravitationally pull the disk up as it comes in, and pull the disk down as it goes through, and this will set up a wave pattern that propagates outward. If you view this in the context of other research that’s emerged in the past two to three years, you start to see a picture is forming.”

The research was funded by the NSF, as well as the Chinese National Science Foundation and the National Basic Research Program of China.

Newberg currently researches the structure and evolution of our own galaxy, using stars as tracers of the galactic halo and disks. These stars in turn are used to trace the density distribution of dark matter in the Milky Way. She has been a participant of the Sloan Digital Sky Survey and is currently head of participants in LAMOST U.S., a partnership allowing U.S. astronomers to take part in a survey of more than 7 million stars by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope in China (LAMOST).

For more information:

Read a publicly available version of the research article

Watch a 20-minute video explaining the findings for the general public

Watch a 50-minute video explaining the findings in greater detail

Contact Information
Mary Martialay
Sr. Communications Specialist
Phone: 518-276-2146
Mobile: 518-951-5650

Mary Martialay | newswise

More articles from Physics and Astronomy:

nachricht Scientists discover particles similar to Majorana fermions
25.10.2016 | Chinese Academy of Sciences Headquarters

nachricht Light-driven atomic rotations excite magnetic waves
24.10.2016 | Max-Planck-Institut für Struktur und Dynamik der Materie

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: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Enormous dome in central Andes driven by huge magma body beneath it

25.10.2016 | Earth Sciences

First time-lapse footage of cell activity during limb regeneration

25.10.2016 | Life Sciences

Deep down fracking wells, microbial communities thrive

25.10.2016 | Earth Sciences

More VideoLinks >>>