"It should appear again elsewhere"

http://www.nytimes.com/2015/03/06/science/astronomers-observe-supernova-and-find-theyre-watching-reruns.html?partner=EXCITE&ei=5043&_r=0

The New York Times


Astronomers Observe Supernova and Find They’re Watching Reruns

By DENNIS OVERBYE MARCH 5, 2015

It’s “Groundhog Day” in the cosmos.

In the 1993 Bill Murray movie, a weatherman finds himself reliving the same day over and over again. Now astronomers using the Hubble Space Telescope say they have been watching the same star blow itself to smithereens in a supernova explosion over and over again, thanks to a trick of Einsteinian optics.

The star exploded more than nine billion years ago on the other side of the universe, too far for even the Hubble to see without special help from the cosmos. In this case, however, light rays from the star have been bent and magnified by the gravity of an intervening cluster of galaxies so that multiple images of it appear.

Four of them are arranged in a tight formation known as an Einstein Cross surrounding one of the galaxies in the cluster. Since each light ray follows a different path from the star to here, each image in the cross represents a slightly different moment in the supernova explosion.

This is the first time astronomers have been able to see the same explosion over and over again, and its unique properties may help them better understand not only the nature of these spectacular phenomena but also cosmological mysteries like dark matter and how fast the universe is expanding.

“I was sort of astounded,” said Patrick Kelly of the University of California, Berkeley, who discovered the supernova images in data recorded by the space telescope in November. “I was not expecting anything like that at all.”

Dr. Kelly is lead author of a report describing the supernova published on Thursday in the journal Science.

Robert Kirshner, a supernova expert at the Harvard-Smithsonian Center for Astrophysics who was not involved in the work, said: “We’ve seen gravitational lenses before, and we’ve seen supernovae before. We’ve even seen lensed supernovae before. But this multiple image is what we have all been hoping to see.”

Supernovas are among the most violent and rare events in the universe, occurring perhaps once per century in a typical galaxy. They outshine entire galaxies, spewing elemental particles like oxygen and gold out into space to form the foundations of new worlds, and leaving behind crushed remnants called neutron stars or black holes.

Because of the galaxy cluster standing between this star and the Hubble, “basically, we got to see the supernova four times,” Dr. Kelly said. And the explosion is expected to appear again in another part of the sky in the next 10 years. Timing the delays between its appearances, he explained, will allow astronomers to refine measurements of how fast the universe is expanding and to map the mysterious dark matter that supplies the bulk of the mass and gravitational oomph of the universe.

The heavens continue to light candles for Albert Einstein. On March 14 he would have been 136, and this year marks a century since his greatest achievement, the general theory of relativity that transformed our understanding of space, time and gravity. Dr. Kelly’s paper appears in a special issue of Science devoted to the anniversary of that theory.

Einstein proposed that matter and energy warp the geometry of space the way a heavy body sags a mattress, producing the effect we call gravity. One consequence of this was that even light rays would be bent by gravity and follow a curved path around massive objects like the sun, as dramatically confirmed during a solar eclipse in 1919.

In effect, space itself could become a telescope.

How this cosmic telescope works depends on how the stars are aligned. If a star and its intervening lens are slightly out of line, the distant light can appear as arcs. If they are exactly lined up, the more distant star can appear as a halo known as an Einstein ring, or as evenly separated images — the Einstein Cross.

Astronomers have learned how to use entire galaxies and galaxy clusters as telescopes to see fainter objects beyond them that would otherwise be lost in the fog of time.

Hubble scientists have recently been using this trick in a program known as Glass, or Grism Lens-Amplified Survey from Space, to explore around clusters of galaxies, the most massive and thus most powerful gravitational lenses in the universe. This has enabled them to extend Hubble’s already powerful vision deeper into the past, in one case to a galaxy that existed when the universe was only half a billion years old.

Dr. Kelly’s job was to inspect the images for distant supernovas. He was not expecting to see four versions of the same explosion at once.

They appeared in images recorded in November of a spiral galaxy roughly nine billion light-years from here. The light from this spiral has been bent and magnified both by the gravity of the intervening cluster, which is five billion light-years distant, and by one very massive galaxy in the cluster.

As a result, ghost images of the spiral appear throughout the cluster and in particular in an Einstein Cross around that one galaxy. Because the lensing effect gathers light that would not otherwise be sent to our eyes or a telescope, the image of the host galaxy is not split so much as multiplied, explained Adi Zitrin, a team member from the California Institute of Technology.

“We see simply see more appearances than we would if the lens were not present,” he said.

So far the supernova, named after a Norwegian astrophysicist, Sjur Refsdal, has been detected in only the four images in the Einstein cross. Based on computer modeling of the cluster, Dr. Kelly and his colleagues suspect that Supernova Refsdal has appeared before, around 1964 and 1995, in other lensed images of the spiral galaxy.

It should appear again elsewhere in the same cluster within the next few years, Dr. Kelly’s team predicts. The exact timing of Supernova Refsdal’s reappearance depends on how the dark matter in the galaxy cluster is distributed, which will tell astronomers much about a part of the universe they cannot see any other way. The longer the path length or the stronger the gravitational field the light ray goes through, the longer the delay.

Or, as Dr. Kirshner said he liked to tell Dr. Kelly, who was his student, “The visible traces the invisible, Grasshopper.”

It takes only about 100 seconds for a star to collapse in a typical supernova, but the resultant outburst of light can last two or three months before declining sharply. Dr. Kelly suspects that his team caught the supernova within weeks of its initial outburst, and it might be a long vigil waiting for the downturn.

Because of the expansion of the universe, the star and its galaxy are receding from us so fast that, according to relativity, clocks there appear to run markedly more slowly than clocks here. As a result, two months from the point of view of the supernova corresponds to nearly six months on Earth.

From our point of view, Dr. Kelly said, “it’s going on in slow motion.”

A star might die only once, but with Einstein’s telescope, if you know where to look, you can watch it scream forever.










JOURNAL ARCHIVE: Posted by H.V.O.M at 9:07 AM Sunday, March 18, 2012


I remember writing about something similar in my private journal on my private internet-connected firewall-enabled Microsoft Windows personal computer back when I lived in that apartment in Kent Washington State in the first half of the year 2005.

I remember I was writing in my journal about my questions about how scientists could depend on their methods of measuring the size of the universe. I had read a little about it and I wondered how those measurements were affected by the bending of light as it traveled through the universe and especially at those extreme distances. If gravity bends light then how can you measure the shift of the wavelength and use that to determine distance? That was what I was wondering about in my notes. Thinking about it more I wonder if it matters though. I can think of some reasons why it might not matter. I don't know. I don't work in that field.

So anyway, I was also thinking again about how I went to the police department in the City of Kent Washington to complain about Microsoft stealing my identity and of how I was falsely imprisoned in the mental health unit for three days at St. Francis Hospital in Federal Way Washington.

They drugged me secretly right from the start so my willful consent is completely destroyed right there, right from the start. I was just expecting to talk.

On the same day the psychiatrist at the hospital told me specifically over the phone that nothing was wrong with me, I went back to that City of Kent police department later that month, having gone there initially on 4 May 2005, and I wanted to follow up with the police officer I spoke to first. After waiting a while in the lobby, the receptionist sent me over to an adjoining building to talk to Detective Murray. I went up the elevator, a guy passed me in the hallway, I got to a telephone outside a locked door on the floor I was supposed to go to, I called Detective Murray at the number the receptionist gave me, I got his voice mail, I left a message, the guy I passed in the hallway was standing at the elevator looking back at me, he asked who I was looking for, I told him, he told me that he was Detective Murray, and then we spoke for a few minutes. All I got from him was some kind of bullshit story. That's what he said. I haven't done anything.


[JOURNAL ARCHIVE 18 March 2012 excerpt ends]



- posted by H.V.O.M - Kerry Wayne Burgess 12:42 PM Pacific Time Spokane Valley Washington USA Thursday 05 March 2015