n2doc

n2doc's Journal

March 19, 2015

A Possible Detection of Dark Matter in a Dwarf Galaxy!

by Ben Cook

Most readers of this blog have likely heard of dark matter before; you may even take it for granted that it exists. A huge body of astronomical research exists offering conclusive evidence for some kind of mass in the universe which a) exerts gravitational force on regular matter, b) doesn’t emit light, and c) seems to be 5 times more abundant than regular matter. Evidence for this extra mass comes from gravitational effects, including

The high velocities of stars/gas in galaxies, and of galaxies in larger clusters
The oscillations of the CMB power spectrum
Direct measurements of cluster masses from gravitational lensing (Fig. 1)
These observations indicate that there is much more mass in the universe than we can see with light.

But these gravitational clues are only “indirect evidence” for dark matter’s existence. It is like seeing a dancing marionette puppet (the gravitational effects), and inferring there must be strings (dark matter) to make it move.

Some models (such as Modified Newtonian Dynamics) try to explain these gravitational effects through a subtle change to General Relativity. These changes could make gravity stronger in certain places without requiring more mass. This explanation is like saying the puppet is held up by magnets: it could explain the puppet’s movement just as well as strings could. To prove dark matter really exists, we must actually see the strings, not just the puppet. Today’s paper offers some of the best evidence yet!

more

http://astrobites.org/2015/03/18/a-possible-detection-of-dark-matter-in-a-dwarf-galaxy/

March 19, 2015

Netanyahu Unmasks Israel

For years, U.S. politicians have rejected allegations of Israeli racism and excused mistreatment of the Palestinians as a temporary necessity that would be fixed by a two-state solution. But Israeli Prime Minister Netanyahu has destroyed those arguments in his panic to keep his job.
by Robert Parry

Desperate to win reelection, Israeli Prime Minister Benjamin Netanyahu stripped off Israel’s mask and exposed the ugliness that has deformed his country over the past several decades. He abandoned the subterfuge of a two-state solution, exposed the crass racism that underlies Israeli politics, and revealed Israel’s blatant control of the U.S. Congress.

For years, these realities were known to many Americans, but – if they spoke up – they were condemned as anti-Semites, so most stayed silent to protect their careers and reputations. But – given Netanyahu’s brazen admissions – the American people may have little choice but to finally take notice of this troubling reality and demand a change in U.S. policy.

The truth is that the two-state solution has been a fiction for at least the past two decades, dying in 1995 with the assassination of Prime Minister Yitzhak Rabin. But the two-state illusion still served important political purposes both for Israelis, who would pay it lip service while continuing their steady encroachment on Palestinian lands, and for U.S. politicians who could point to the mirage as an excuse not to pressure Israel too hard on its human rights violations.

Yet, whenever any U.S. official actually tried to reach that shimmering oasis of a two-state solution, it would recede into the distance. Then, the Israelis would rely on their friends and allies in the news media and politics to blame the Palestinians. Now, however, the illusion of Israel seeking such an outcome in good faith has been lost in Netanyahu’s anything-goes determination to keep his office – a case of political expediency trumping strategic expediency.

more

http://www.commondreams.org/views/2015/03/19/netanyahu-unmasks-israel

March 19, 2015

Thursday TOON Roundup 3- The Rest

Climate

Letter

Mideast

Ill.

Race

Chez Ronald

2016

Rights

NCAA

Football

Gawd

March 19, 2015

Thursday Toon Roundup 2- GOP

March 19, 2015

Thursday Toon Roundup 1- Drop Dead, Mid eastern Peace Dove

March 19, 2015

A Visualization Depicts a Sunset With the Sun Replaced by Other Stars

(yes yes I realize that the environmental conditions would vary greatly with different stars at the same distance, still an interesting visualization)

http://laughingsquid.com/a-visualization-depicts-a-sunset-with-the-sun-replaced-by-other-stars/

March 18, 2015

Every Star Could Have at Least One Planet That Could Support Liquid Water

Astronomers worldwide agree: there's a heck of a lot of planets out there. Thanks to tools like the Kepler Space Telescope, scientists have been discovering hundreds of new planets each year, and many believe it's only a matter of time until we find one very similar to our own earth. The big question now is, just how common are planets, and how many of them can we expect to look like Earth—or least hold liquid water?

In new study, researchers led by Steffen Jacobsen at the Niels Bohr Institute in Denmark have taken a crack at these questions and come up with some pretty stunning conclusions. By extrapolating on recent planet discoveries found though the Kepler mission, the astronomers have estimated that, on average, every star has between one to three planets nestled into its liquid water-supporting habitable zone. And of those planets, one in six should be rocky like the Earth, Jacobsen says.

"In our galaxy alone, this would mean billions and billions of planets [in their star's habitable zones], with very good chances at finding an Earth twin," Jacobsen says. "But to be clear, these numbers are highly dependent on many assumptions at work here."

How they got those numbers
Since it started staring at the stars in 2009, Kepler has spotted hundreds of new planets and many more planet candidates that could be confirmed in time. It upended what we know and how we think about what's out there in the cosmos.

more

http://www.popularmechanics.com/space/a14619/every-star-could-have-at-least-one-planet-that-could-support-liquid-water/

March 18, 2015

Neil deGrasse Tyson's late night TV show will premiere on 4/20

Self medication is not required for the enjoyment of late night television

By Chris Plante

Astrophysicist and guy I occasionally see on the subway, Neil deGrasse Tyson will premiere his new late night program StarTalk on National Geographic Channel on April 20th, according to the cable network. Variety reports that guests will include, "Former US president Jimmy Carter, biologist Richard Dawkins, retired Canadian astronaut Chris Hadfield, producer Norman Lear, film director Christopher Nolan, and Star Trek actor George Takei."

If you haven't listened to the podcast that inspired the television show and shares its name, now is as fine a time as any to start. StarTalk: The Radio Show is a humorous and human take on scientific topics that can too often feel cold, distant, and incomprehensible to laypeople — like myself. The late night series will regularly feature fellow scientist and television personality Bill Nye, along with a slew of comedians, scientists, and celebrities.

StarTalk premiers Monday, April 20th at 11PM EST. The competitive linking of Neil deGrasse Tyson memes in the comments begins now.

http://www.theverge.com/2015/3/18/8252023/neil-degrasse-tyson-startalk-late-night-tv-420