Tag: astronomy

Voyager 1 at the edge

10:31 am

This week the American Geophysical Union (AGU) is having its annual fall meeting in San Francisco. Due to the wonders of technology, they are now making their press conferences available to reporters on line. Thus, I will be posting periodic updates after each conference. This will allow my readers to get a heads up on stories they will be seeing in the mainstream press in the next few hours.

Right now they are wrapping up a press conference from the team of the Voyager 1 spacecraft, in which they have described the spacecraft’s status.
» Read more

One comment

The first observations of a star, just prior to going supernova

1:30 pm

Astronomers have for the first time observed the changes that took place in a binary star system in the years before one star in the system erupted as a supernova.

In the first survey of its kind, the researchers have been scanning 25 nearby galaxies for stars that brighten and dim in unusual ways, in order to catch a few that are about to meet their end. In the three years since the study began, this particular unnamed binary system in the Whirlpool Galaxy was the first among the stars they’ve cataloged to produce a supernova.

The astronomers were trying to find out if there are patterns of brightening or dimming that herald the end of a star’s life. Instead, they saw one star in this binary system dim noticeably before the other one exploded in a supernova during the summer of 2011.

Key quote: “Our underlying goal is to look for any kind of signature behavior that will enable us to identify stars before they explode,”

The supernova in question, 2011dh, was the closest supernova in decades, occurring in June 2011 in the Whirlpool Galaxy (M51). See my previous posts here and here.

Leave a comment

‘Perfect black’ coating can render a 3D object flat, raises intriguing dark veil possibility in astronomy

12:27 pm

A newly developed “perfect black” coating can render a 3D object flat, which raises an intriguing dark veil possibility in astronomy.

“The carbon nanotube forest can absorb very wide range of electromagnetic wave from ultraviolet up to terahertz,” Guo said, “and in principle it can be applied to an arbitrary sized object.” Just how large an object? Guo suggested an intriguing possibility—perhaps entire planets or even stars. “Since deep space itself is a perfect dark background, if a planet or star were surrounded by a thick, sooty atmosphere of light-absorbing carbon nanomaterial gases, it would become invisible due to the same principle,” Guo said. “It would become totally dark to our instruments that rely on the detection of electromagnetic waves.”

Leave a comment

Astronomers have proposed that the cloud of dust that surrounds about 50% of the supermassive black holes at the center of galaxies comes from destroyed planets

8:13 am

Science better than fiction: Astronomers have proposed that the cloud of dust surrounding about 50% of the supermassive black holes at the center of galaxies comes from planets that were ripped apart and smashed by that black hole.

Collisions between these rocky objects would occur at colossal speeds as large as 1000 km per second, continuously shattering and fragmenting the objects, until eventually they end up as microscopic dust. Dr. Nayakshin points out that this harsh environment – radiation and frequent collisions – would make the planets orbiting supermassive black holes sterile, even before they are destroyed. “Too bad for life on these planets”, he says, “but on the other hand the dust created in this way blocks much of the harmful radiation from reaching the rest of the host galaxy. This in turn may make it easier for life to prosper elsewhere in the rest of the central region of the galaxy.”

Leave a comment

According to Zubrin, Obama about to terminate all NASA science

8:32 am

According to Robert Zubrin, the Obama administration is planning to terminate all funding to NASA’s planetary program, while cutting back significantly on its astronomy program.

Word has leaked out that in its new budget, the Obama administration intends to terminate NASA’s planetary exploration program. The Mars Science Lab Curiosity, being readied on the pad, will be launched, as will the nearly completed small MAVEN orbiter scheduled for 2013, but that will be it. No further missions to anywhere are planned. After 2013, America’s amazing career of planetary exploration, which ran from the Mariner probes in the 1960s through the great Pioneer, Viking, Voyager, Pathfinder, Mars Global Surveyor, Mars Odyssey, Spirit, Opportunity, Mars Reconnaissance Orbiter, Galileo and Cassini missions, will simply end.

Furthermore, the plan from the Office of Management and Budget (OMB) also leaves the space astronomy program adrift and headed for destruction. The now-orbiting Kepler Telescope will be turned off in midmission, stopping it before it can complete its goal of finding other Earths. Even worse, the magnificent Webb Telescope, the agency’s flagship, which promises fundamental breakthroughs in our understanding of the laws of the universe, is not sufficiently funded to allow successful completion. This guarantees further costly delays, with the ensuing budgetary overruns leading inevitably to eventual cancellation.

I suspect these cuts have been leaked now, months before the budget is publicly released, in order to whip up support for funding these programs. I also find it distressing that these programs, which cost practically nothing, are targets, while others that cost many many more billions (in NASA and elsewhere) remain fully funded.

10 comments

Has dark matter been identified?

9:21 am

From a paper published today on the Los Alamos astro-ph preprint website, scientists suggest that three different physics experiments might have identified dark matter. From the abstract:

Three dark matter direct detection experiments (DAMA/LIBRA, CoGeNT, and CRESST-II) have each reported signals which are not consistent with known backgrounds, but resemble that predicted for a dark matter particle with a mass of roughly ~10 GeV. . . . In this article, we compare the signals of these experiments and discuss whether they can be explained by a single species of dark matter particle, without conflicting with the constraints of other experiments. We find that the spectrum of events reported by CoGeNT and CRESST-II are consistent with each other and with the constraints from CDMS-II, although some tension with xenon-based experiments remains. Similarly, the modulation signals reported by DAMA/LIBRA and CoGeNT appear to be compatible, although the corresponding amplitude of the observed modulations are a factor of at least a few higher than would be naively expected, based on the event spectra reported by CoGeNT and CRESST-II. This apparent discrepancy could potentially be resolved if tidal streams or other non-Maxwellian structures are present in the local distribution of dark matter.

The last sentence above suggests that the differences between the various experiments might be explained by the motion of dark matter itself as it flows through the solar system.

This conclusion is very tentative. The scientists admit that there remain conflicts between the results of the three experiments, and that there also could be explanations other than dark matter for the results. Furthermore, the results of other experiments raise questions about this conclusion.

Nonetheless, it appears that physicists might be closing in on this most ghostlike of all particles in the universe.

Leave a comment
1 … 54 55 56 57 58 … 66