Did the Milky Way Have a Encounter with a Massive Dark Matter Structure 100 Million Years Ago?
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June 29, 2012

Did the Milky Way Have a Encounter with a Massive Dark Matter Structure 100 Million Years Ago?

 

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"Our Milky Way had an encounter with a small galaxy or massive dark matter structure perhaps as recently as 100 million years ago," said Larry Widrow, professor at Queen’s University, part of a team of astronomers from Canada and the United States who have discovered what may well be the smoking gun of such an encounter, one that occurred close to our position in the galaxy and relatively recently, at least in the cosmological sense. "We clearly observe unexpected differences in the Milky Way’s stellar distribution above and below the Galaxy’s midplane that have the appearance of a vertical wave -- something that nobody has seen before," Widrow added.

The discovery is based on observations of some 300,000 nearby Milky Way stars by the Sloan Digital Sky Survey. Stars in the disk of the Milky Way move up and down at a speed of about 20-30 kilometers per second while orbiting the ce nter of the galaxy at a brisk 220 kilometers per second. Widrow and his four collaborators from the University of Kentucky, the University of Chicago and Fermi National Accelerator Laboratory have found that the positions and motions of these nearby stars weren’t quite as regular as previously thought.

"Our part of the Milky Way is ringing like a bell," said Brian Yanny, of the Department of Energy’s Fermilab. "But we have not been able to identify the celestial object that passed through the Milky Way. It could have been one of the small satellite galaxies that move around the center of our galaxy, or an invisible structure such as a dark matter halo."

 "The perturbation need not have been a single isolated event in the past, and it may even be ongoing. Additional observations may well clarify its origin," added Susan Gardner, professor of physics at the University of Kentucky.

When the collaboration started analyzi ng the SDSS data on the Milky Way, they noticed a small but statistically significant difference in the distribution of stars north and south of the Milky Way's midplane. For more than a year, the team members explored various explanations of this north-south asymmetry, such as the effect of interstellar dust on distance determinations and the way the stars surveyed were selected. When those attempts failed, they began to explore the alternative explanation that the data was telling them something about recent events in the history of the Galaxy.

The scientists used computer simulations to explore what would happen if a satellite galaxy or dark matter structure passed through the disk of the Milky Way. The simulations indicate that over the next 100 million years or so, our galaxy will "stop ringing:" the north-south asymmetry will disappear and the vertical motions of stars in the solar neighborhood will revert back to their equilibrium orbits -- unless we get hit again.

The Milky Way is more than 9 billion years old with about 100 billion stars and total mass more than 300 billion times that of the sun. Most of the mass in and around the Milky Way is in the form of dark matter.

Scientists know of more than 20 visible satellite galaxies that circle the center of the Milky Way, with masses ranging from one million to one billion solar masses. There may also be invisible satellites made of dark matter. (There is six times as much dark matter in the universe as ordinary, visible matter.) Astronomers' computer simulations have found that this invisible matter formed hundreds of massive structures that move around our Milky Way.

Because of their abundance, these dark matter satellites are more likely than the visible satellite galaxies to cut through the Milky Way’s midplane and cause vertical waves.

"Future astronomical programs, such as the space-based Gaia Mission, will be able t o map out the vertical perturbations in our galaxy in unprecedented detail," Widrow said. "That will offer a strong test of our findings."

The results have been published in The Astrophysical Journal Letters: http://iopscience.iop.org/2041-8205/750/2/L41/pdf/2041-8205_750_2_L41.pdf

The Daily Galaxy via Fermi Lab

Comments

These people seem to be developing an unfortunate disconnect from reality.'Dark matter' exists only between their ears and the Earth is NOT flat. The rest is whale sushi :-)

Dark Matter is one thing, invisible matter another... let's be consistent shall we... and as yet, nothing is proven either way.

GALACTIC CYCLICAL FORMATION EXPLAINS IT

There is no need to include “dark matter” in order to solve this problem. The whole galactic scenario shall be seen in the light of the whirling complexity of circuits in the galaxy.

The galactic formation of gas and particles in the galaxy goes from the atomic level to the formation of stars and planets –and back again to the atomic level. That is: The formation circuit changes between formation and dissolving everything in a cyclical way.

The cyclical stages of Galactic Formation:

1) Larger spheres of gas and matter (stars and planets etc.) flow into the swirling galactic funnel (the so called black hole) of the galaxy and into the center of the galaxy. (This takes place both above and below the Galaxy’s midplane in a so called “double layer” formation)

2) In the middle of the galaxy, these larger spheres of stars and planets are dissolved and re-formatted via nuclear processes and formed to new stars and planets.

3) The dissolving process creates large electromagnetic swirling gamma ray circuits going vertically out on both sides of the galactic midplane.

4) The re-formation of the stars and planets and their “rebirth” takes place via a swirling and circular motion out in the galactic bars and further out in the galactic arms – and back again into the centre of the galaxy where it starts all over again.

Quote: “Stars in the disk of the Milky Way move up and down at a speed of about 20-30 kilometers per second while orbiting the center of the galaxy”.

AD: This “up and down/circular” motion origin from the horizontal and circular motion of new stars and planets moving horizontally out in the barred structures in the rotating Milky Way. (#4)

One has to imagine the galactic barred formation structure as a tube in which the stars and planets are whirling horizontally out from the galactic centre as in an electromagnetic circular polarization, so the motion is NOT “up and down”, but circular.

Both the rotation of stars and planets and the orbit of a planet gains motion and velocity from the whirling nuclear formation centre in swirling the galaxy.

- This explanation is contra dictionary to the ordinary formation theory of our Solar System, and it explains both the “up and down”-circular motion of the solar system as well as it explain the “galactic rotation anomaly” where stars and planets etc., all moves relative similar in the galaxy because of its common circuit motions.

Ivar Nielsen
Natural Philosopher

Love it. Mention dark matter/energy = Summon Ivar


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