Science & TechnologyS


Comet

Comet ISON: Is potential 'Comet of the Century' already fizzling out?

Mike Wall
SPACE.com
Tue, 30 Jul 2013 11:00 UTC
ISON_1
© NASA, ESA, and the Hubble Heritage Team (STScI/AURAThe Hubble Space Telescope captured this view of Comet ISON, C/2012 S1 (ISON), on May 8, 2013 as it streaked between the orbits of Jupiter and Mars at a speed of about 48,000 mph.
It doesn't look like Comet ISON will live up to the considerable hype, one researcher says.

ISON has been billed as a potential "comet of the century," with some experts saying it could blaze as brightly as the full moon around the time of its close solar approach in late November. But the comet's recent behavior suggests that such a dazzling show is not in the cards, says astronomer Ignacio Ferrín of the University of Antioquia in Medellín, Colombia.

"Comet ISON has presented a peculiar behavior," Ferrín said in a statement Monday (July 29). "The light curve has exhibited a 'slowdown event' characterized by a constant brightness, with no indication of a brightness increase tendency. This slowdown took place around January 13th, 2013. For 132 days after that date and up to the last available observation, the brightness has remained constant."

Comment: Others have a different view - Rumors of Comet ISON 'fizzling' may be greatly exaggerated

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Info

Einstein's cosmic speed limit still reigns, for now

Clara Moskowitz
LiveSciene
Mon, 29 Jul 2013 15:41 UTC
Speed of Light
© Iscatel/ShutterstockEinstein's theory of special relativity sets of the speed of light, 186,000 miles per second (300 million meters per second). But some scientists are exploring the possibility that this cosmic speed limit changes.
The speed of light is considered to be the ultimate cosmic speed limit, thanks to Einstein's special theory of relativity. But physicists aren't content to assume this limit without testing it.

That's where a new experiment with electrons comes in. Physicists measured the energy required to change the speed of electrons as they hopped from one orbital to another inside atoms of dysprosium, all while Earth rotated over a 12-hour period. This allowed the scientists to measure that the maximum speed of an electron, which, according to special relativity should be the speed of light, is the same in all directions to within 17 nanometers per second. This measurement was 10 times more precise than previous tests of electrons' maximum speed.

So far, Einstein still comes out on top, and the theory holds. But the researchers hope to follow up the experiment with a more precise trial that might prove capable of poking holes in special relativity. That could actually be a good thing, scientists say, at least in terms of the advancement of physics.

"As a physicist, I want to know how the world works, and right now our best models of how the world works - the Standard Model of particle physics and Einstein's theory of general relativity - don't fit together at high energies," physicist Michael Hohensee of the University of California, Berkeley, said in a statement. "By finding points of breakage in the models, we can start to improve these theories."
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Question

Is gravity weirder than we think?

Bob Berman
HudsonValleyAlmanacWeekly
Mon, 29 Jul 2013 18:41 UTC
MOND Theory
© BBC "Low surface brightness" galaxies like F549-1 lend greater precision to the Mond theory's predictions.
We've long known that our Milky Way galaxy will collide with its neighbor Andromeda in about four billion years. But some European astronomers think this is a case of deja vu - that we have collided once before, long ago. This would explain puzzling structures in both our galaxies, and the odd existence of our tiny satellite galaxies like the Magellanic clouds.

But it would mean that dark matter does not exist. And our ideas about how gravity behaves on large scales, is wrong. It would change everything.

In 1930, the brilliant astronomer Fritz Zwicky noticed that the way groups of galaxies stay together despite their large individual speeds shows that they contain about six times more gravity than can be explained by all their stars, planets, black holes, and everything else.

The way our galaxy spins supports this, too. Some unseen entity that has gravity must dominate the scene everywhere, and we call this dark matter. This is what must be gravitationally pulling us toward Andromeda at 70 mps so that the two of us can overcome the universe's expansion.
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Igloo

Solar Cycle #24: On track to be the weakest in 100 years

David Dickinson
Universe Today
Mon, 29 Jul 2013 17:23 UTC
Sunspots
© Hathaway/NASA/MSFCProjected vs observed sunspot numbers for solar cycles #23 & #24.
Our nearest star has exhibited some schizophrenic behavior thus far for 2013.

By all rights, we should be in the throes of a solar maximum, an 11-year peak where the Sun is at its most active and dappled with sunspots.

Thus far though, Solar Cycle #24 has been off to a sputtering start, and researchers that attended the meeting of the American Astronomical Society's Solar Physics Division earlier this month are divided as to why."Not only is this the smallest cycle we've seen in the space age, it's the smallest cycle in 100 years," NASA/Marshall Space Flight Center research scientist David Hathaway said during a recent press teleconference conducted by the Marshall Space Flight Center.

Cycle #23 gave way to a profound minimum that saw a spotless Sol on 260 out of 365 days (71%!) in 2009. Then, #Cycle 24 got off to a late start, about a full year overdue - we should have seen a solar maximum in 2012, and now that's on track for the late 2013 to early 2014 time frame. For solar observers, both amateur, professional and automated, its seems as if the Sun exhibits a "split-personality" this year, displaying its active Cycle #24-self one week, only to sink back into a blank despondency the next.
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Sun

Space telescope spots giant 'hole' in the Sun


Yahoo! News
Mon, 29 Jul 2013 12:14 UTC

The Solar and Heliospheric Observatory space telescope spotted an enormous hole in the sun's burning atmosphere. Jen Markham explains the phenomena and why such holes really are surprisingly common.
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Saturn

Just one small dot on the landscape: the spectacular Earth taken from Saturn, 900 million miles away

Michael Zennie
Mail Online
Mon, 22 Jul 2013 13:23 UTC
earth from saturn
A tiny spot: Planet Earth can been seen as just a miniscule star from this enhanced shot of Saturn taken by the NASA spacecraft Cassini nearly 900million miles away
Earth appears as an insignificant-looking pale blue dot below Saturn's majestic rings in a breathtaking new image from the Cassini spacecraft.

The picture was captured on July 19 by the probe's wide-angle camera from a distance of 900 million miles.

Magnifying the image five times reveals not only the Earth but also the moon, a fainter smudge to the right of the planet.
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Meteor

NASA hasn't a clue how to deal with risk of cometary bombardment, so agency is tendering bids for 'safely relocating' incoming space rocks!

Tariq Malik
Huffington Post
Mon, 29 Jul 2013 06:02 UTC
Image
© NASAPipe-dream: A 'notional concept' of a solar-electric-powered spacecraft, designed to "capture a small near-Earth asteroid and relocate it safely", close to the Earth-moon system "so astronauts can explore it." Yeh, right!
A NASA call for novel ideas on how to tackle its ambitious mission to capture an asteroid and park it near the moon has paid off in spades, with the agency receiving hundreds of proposals from potential partners.

NASA has received more than 400 proposals from private companies, non-profit groups and international organizations in response to a call for asteroid-retrieval mission suggestions released last month, agency officials announced Friday (July 26). The space agency will review the submissions over the next month and plan to discuss the most promising ideas in a public workshop in September.

"We are really excited about the overwhelming response," NASA Deputy Administrator Lori Garver told reporters here at the NewSpace 2013 conference, adding that the ideas were "overwhelmingly positive."

NASA put out an official request for information on June 18 to seek input on how to achieve its asteroid retrieval mission. That asteroid capture plan, which NASA unveiled in April, is known as the agency's Asteroid Initiative.
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Fireball 5

Close approach of Asteroid 2003 DZ15

Ernesto Guido & Nick Howes
Remanzacco Observatory
Sun, 28 Jul 2013 21:38 UTC
M.P.E.C. 2013-O29, issued on 2013 July 20, reports the recovery of the Apollo asteroid 2003 DZ15 (magnitude 18) by F51 Pan-STARRS 1, Haleakala, on images taken on July 19.4 with a 1.8-m Ritchey-Chretien + CCD.

2003 DZ15 was discovered on February 2003 by 608 Haleakala-NEAT/MSSS and it has an estimated size of 95 m - 210 m (based on the object's absolute magnitude H=22.2) and it will have a close approach with Earth at about 9.1 LD (Lunar Distances = ~384,000 kilometers) or 0.0233 AU (1 AU = ~150 million kilometers) at 0037 UT on 2013 July 30. This asteroid will reach the peak magnitude ~16.5 on 29 and 30 July 2013. This is its closest approach to the Earth for this century, although it will make a pass nearly as close to the Earth in 2057 on February 12th.

We performed some follow-up measurements of this object, from the Q62 ITelescope network (Siding Spring, AU) on 2013, July 28.6, through a 0.50-m f/6.8 astrograph + CCD + focal reducer. Below you can see our image, single 120-second exposure, taken with the asteroid at magnitude ~16.6 and moving at ~40.80 "/min. At the moment of the close approach 2003 DZ15 will move at ~52 "/min. Click on the image below to see a bigger version (the asteroid is trailed in the image due to its fast speed).
Asteroid 2003 DZ15
© Remanzacco Observatory
Here you can see a short animation showing the movement of 2003 DZ15 (three consecutive 120-second exposure).
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Bulb

Evolution on the inside track: Penn study shows how viruses in gut bacteria change over time


Penn Medicine
Fri, 26 Jul 2013 17:30 UTC
Image
© Frederick Bushman, PhD, Perelman School of Medicine, University of Pennsylvania; PNASPhylogenetic tree of microphages detected in PNAS study and other studies. The four microphage contigs with the highest substitution rates observed in the PNAS study are shown in large black lettering. The scale bar indicates the proportion of amino acid substitutions within the 919 amino acid major coat protein, which was aligned to make the tree.
Implications for Deciphering Differences in Disease Susceptibility, Drug Resistance and Effectiveness.

Humans are far more than merely the sum total of all the cells that form the organs and tissues. The digestive tract is also home to a vast colony of bacteria of all varieties, as well as the myriad viruses that prey upon them. Because the types of bacteria carried inside the body vary from person to person, so does this viral population, known as the virome.

By closely following and analyzing the virome of one individual over two-and-a-half years, researchers from the Perelman School of Medicine at the University of Pennsylvania, led by professor of MicrobiologyFrederic D. Bushman, Ph.D., have uncovered some important new insights on how a viral population can change and evolve - and why the virome of one person can vary so greatly from that of another. The evolution and variety of the virome can affect susceptibility and resistance to disease among individuals, along with variable effectiveness of drugs.

Their work was published in the Proceedings of the National Academy of Sciences.

Most of the virome consists of bacteriophages, viruses that infect bacteria rather than directly attacking their human hosts. However, the changes that bacteriophages wreak upon bacteria can also ultimately affect humans.

"Bacterial viruses are predators on bacteria, so they mold their populations," says Bushman. "Bacterial viruses also transport genes for toxins, virulence factors that modify the phenotype of their bacterial host." In this way, an innocent, benign bacterium living inside the body can be transformed by an invading virus into a dangerous threat.
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Comet

New Comet: C/2013 O3 (McNaught)

Seiichi Yoshida
Aerith Net
Sun, 28 Jul 2013 14:00 UTC
Discovery Date: July 24, 2013

Magnitude: 17.7 mag

Discoverer: Robert H. McNaught (Siding Spring)
C/2013 O3
© Aerith NetMagnitudes Chart
The orbital elements are published on M.P.E.C. 2013-O54.
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