Monday, May 16, 2011
Flippin' Planets from Life Unbounded blog
http://lifeunbounded.blogspot.com/2011/05/flippin-planets.html
A year ago it started to become clear that a significant number of exoplanetary systems harbored retrograde worlds. These planets are seen on small orbits that have the opposite sense to the spins of the stars that host them. This is a peculiar and puzzling arrangement. We've all been brought up to think of planets and stars forming out of the same proto-stellar disk of material and that angular momentum is an almost sacrosanct quantity - can't fiddle around with that. Getting planets to go in the opposite direction is quite unsettling.
Clearly the universe is having none of that silly narrow-minded thinking. However, the question has been how to produce these retrograde worlds; hot Jupiters zipping the "wrong" way around their parent stars in closely circular orbits. A new paper by Naoz and colleagues presents some intriguing and thorough calculations about a couple of phenomena that could do the trick.
They consider pairs of large, gas giant sized, planets that start out in decently large prograde orbits. For example, the inner planet may orbit at 6 astronomical units (AU) from the star, the outer planet at about 60 AU. The trick is to follow what happens if those initial orbits are highly misaligned. In other words if the orbital planes of the two planets are more than 50 degrees inclined with respect to each other. In this type of configuration long term gravitational nudging between the planets - particularly the outer one on the inner one - can result in severe changes in the ellipticity or eccentricity of the inner planet's orbit, as well as its orientation. Over a span of a few hundred thousand years the orbit can not only shift from being nearly circular to being nearly "needle like" (highly elliptical) but its orientation can change dramatically. In the most extreme instances it can quite literally flip, shifting all the way through a 90 degree inclination to more than 90 degrees - in effect going retrograde.
This flip can occur during an eccentricity spike, which I think gives us some physical insight to what happens. At the far point (apastron) of a super high eccentricity orbit the planet is going to be almost hanging in space, slowing to a near standstill before plunging back star-wards. If already on a highly inclined orbit (close to that 90 degrees) then all it will take is a little tug from the outer planet in the right direction to flip the orbit over. It's a bit like that moment of indecision teetering at the top of a snowy hill with skis attached to feet. Left to take the piste, right to go to the bar.
At the same time, an extremely elliptical orbit will bring the planet zooming in from several AU to mere tenths of an AU from the star as the planet screeches through its periastron approach. Naoz et al have computed the strength of star-planet tidal forces and the associated energy dissipation and show that the inner planet can be yanked into a tight circular orbit around the star in an incredibly brief period. A little too close to the honey pot and you get trapped. Once this happens the inner planet is totally decoupled from the outer planet, which simply cannot get its sticky gravitational mitts on the inner world any more. The end result is a close orbiting retrograde hot Jupiter.
Remarkably Naoz et al.'s models even seem to produce about the right fraction of systems in which this will happen. The only hitch is how to set up the initial configuration of planets, particularly with the outer planet on such a large orbit and with such a large mis-alignment between their orbital planes. Luckily an earlier epoch of strong planet-planet gravitational scattering from within the zone of planet formation might just do the trick.
Planetary systems are just so incredibly diverse. And, once again, we find ourselves gazing at our own system and wondering just how far we can or should take the Copernican Principle. This boring little solar system of ours may yet turn out to be a little on the special side.
POSTED BY CALEB SCHARF
A year ago it started to become clear that a significant number of exoplanetary systems harbored retrograde worlds. These planets are seen on small orbits that have the opposite sense to the spins of the stars that host them. This is a peculiar and puzzling arrangement. We've all been brought up to think of planets and stars forming out of the same proto-stellar disk of material and that angular momentum is an almost sacrosanct quantity - can't fiddle around with that. Getting planets to go in the opposite direction is quite unsettling.
Clearly the universe is having none of that silly narrow-minded thinking. However, the question has been how to produce these retrograde worlds; hot Jupiters zipping the "wrong" way around their parent stars in closely circular orbits. A new paper by Naoz and colleagues presents some intriguing and thorough calculations about a couple of phenomena that could do the trick.
They consider pairs of large, gas giant sized, planets that start out in decently large prograde orbits. For example, the inner planet may orbit at 6 astronomical units (AU) from the star, the outer planet at about 60 AU. The trick is to follow what happens if those initial orbits are highly misaligned. In other words if the orbital planes of the two planets are more than 50 degrees inclined with respect to each other. In this type of configuration long term gravitational nudging between the planets - particularly the outer one on the inner one - can result in severe changes in the ellipticity or eccentricity of the inner planet's orbit, as well as its orientation. Over a span of a few hundred thousand years the orbit can not only shift from being nearly circular to being nearly "needle like" (highly elliptical) but its orientation can change dramatically. In the most extreme instances it can quite literally flip, shifting all the way through a 90 degree inclination to more than 90 degrees - in effect going retrograde.
This flip can occur during an eccentricity spike, which I think gives us some physical insight to what happens. At the far point (apastron) of a super high eccentricity orbit the planet is going to be almost hanging in space, slowing to a near standstill before plunging back star-wards. If already on a highly inclined orbit (close to that 90 degrees) then all it will take is a little tug from the outer planet in the right direction to flip the orbit over. It's a bit like that moment of indecision teetering at the top of a snowy hill with skis attached to feet. Left to take the piste, right to go to the bar.
At the same time, an extremely elliptical orbit will bring the planet zooming in from several AU to mere tenths of an AU from the star as the planet screeches through its periastron approach. Naoz et al have computed the strength of star-planet tidal forces and the associated energy dissipation and show that the inner planet can be yanked into a tight circular orbit around the star in an incredibly brief period. A little too close to the honey pot and you get trapped. Once this happens the inner planet is totally decoupled from the outer planet, which simply cannot get its sticky gravitational mitts on the inner world any more. The end result is a close orbiting retrograde hot Jupiter.
Remarkably Naoz et al.'s models even seem to produce about the right fraction of systems in which this will happen. The only hitch is how to set up the initial configuration of planets, particularly with the outer planet on such a large orbit and with such a large mis-alignment between their orbital planes. Luckily an earlier epoch of strong planet-planet gravitational scattering from within the zone of planet formation might just do the trick.
Planetary systems are just so incredibly diverse. And, once again, we find ourselves gazing at our own system and wondering just how far we can or should take the Copernican Principle. This boring little solar system of ours may yet turn out to be a little on the special side.
POSTED BY CALEB SCHARF
Sunday, May 15, 2011
Saturday, May 14, 2011
Thursday, May 12, 2011
Wednesday, May 11, 2011
Tuesday, May 10, 2011
http://www.avaaz.org/en/uganda_stop_homophobia_petition_2/?vl
Dear friends,
In 48 hours, Uganda could pass a law that imposes the death penalty for homosexuality. An international outcry shelved this bill last year -- we urgently need to ramp up the pressure to press President Museveni to stand up for human rights and stop this brutal law. Sign below, and tell everyone:
In 48 hours, the Ugandan Parliament may vote on a brutal new law that carries the death penalty for homosexuality. Thousands of Ugandans could face execution -- just for being gay.
We've helped stop this bill before, and we can do it again. After a massive global outcry last year, Ugandan President Museveni blocked the bill's progress. But political unrest is mounting in Uganda, and religious extremists in Parliament are hoping confusion and violence in the streets will distract the international community from a second push to pass this hate-filled law. We can show them that the world is still watching. If we block the vote for two more days until Parliament closes, the bill will expire forever.
We have no time to lose. Almost half a million of us have already joined the call -- let’s get to one million voices against Uganda's gay death penalty in the next 48 hours -- click here to take action, then forward this email to everyone:
http://www.avaaz.org/en/uganda_stop_homophobia_petition_2/?vl
For Frank and thousands of others, being gay in Uganda is already dangerous and terrifying. They are regularly harassed and beaten, and just months ago, gay rights activist, David Kato (pictured above), was brutally murdered in his own home. Now LGBT Ugandans are threatened by this draconian law which imposes life imprisonment for people convicted of same-sex relations and the death penalty for “serial offenders”. Even NGOs working to prevent the spread of HIV can be imprisoned for “promoting homosexuality” under this hate-filled law.
Right now, Uganda is in political turmoil -- in the wake of the Arab spring, people across the country are taking to the streets, protesting high food and gas prices. President Museveni has responded by violently cracking down on the opposition. This upheaval has provided religious extremists in Parliament the perfect chance to slip in the shelved anti-gay bill just days before Parliament closes and all proposed laws are wiped from the books.
Museveni backed away from this bill last year after international pressure threatened Uganda's aid and support. With violent protests sweeping the streets, Museveni is more vulnerable than ever. In the next 48 hours, let’s build a massive international outcry in support of respect for human rights, justice and tolerance and against the gay death penalty. Together we can save lives by stopping this bill -- sign below, then tell friends and family:
http://www.avaaz.org/en/uganda_stop_homophobia_petition_2/?vl
Earlier this year, we stood in solidarity with Uganda's equality movement to show that every human life, no matter what creed, nationality or sexual orientation, is equally precious. Our international petition condemning the gay death penalty law was delivered to Parliament – spurring a global news story and enough pressure to block the bill for months. When a tabloid newspaper published 100 names, pictures and addresses, of suspected gays and those identified were threatened, Avaaz supported a legal case against the paper and we won! Our community has funded security for gay rights activists and operational funding for gay rights organizations. Together we have stood up, time and time again, for Uganda’s gay community -- now they need us more than ever.
With hope and determination,
Emma, Iain, Alice, Morgan, Brianna and the rest of the Avaaz team
SOURCES:
Ugandan lawmakers hold hearings on anti-gay bill
http://www.google.com/hostednews/ap/article
Uganda gay activist Kasha Jacqueline Nabagesera hailed
http://www.bbc.co.uk/news/world-africa-13278374
Pulling Out All the Stops to Push an Antigay Bill
http://www.nytimes.com/2011/04/14/world/africa/14uganda.html
Support the Avaaz community! We're entirely funded by donations and receive no money from governments or corporations. Our dedicated team ensures even the smallest contributions go a long way -- donate here.
Monday, May 9, 2011
“He was really a nice guy. He went to church and everything.”
fROM THE BLOG OF pHARYNGULA
Category: Crime • Evil
Posted on: May 9, 2011 11:38 AM, by PZ Myers
Those are ominous words. Brian and Shannon Gore have been arrested after police, investigating evidence that Shannon Gore had been selling stolen goods, found their 5 or 6 year old daughter caged in their trailer home, gnawing on her own skin.
Then they found the body of another child buried under a shed.
Fine upstanding members of the Christian community, they are.
I don't consider every Christian to be a child-torturing murderer, but one thing I wish we could get across is that church attendance has nothing to do with morality or ethical behavior or goodness of any kind. So why do so many people consider a weekly session with a deranged, delusional ranter in a pulpit to be a seal of approval?
BIN lADEN, Mugabe, Members of the mafia are all very religious persons
Category: Crime • Evil
Posted on: May 9, 2011 11:38 AM, by PZ Myers
Those are ominous words. Brian and Shannon Gore have been arrested after police, investigating evidence that Shannon Gore had been selling stolen goods, found their 5 or 6 year old daughter caged in their trailer home, gnawing on her own skin.
Then they found the body of another child buried under a shed.
Fine upstanding members of the Christian community, they are.
I don't consider every Christian to be a child-torturing murderer, but one thing I wish we could get across is that church attendance has nothing to do with morality or ethical behavior or goodness of any kind. So why do so many people consider a weekly session with a deranged, delusional ranter in a pulpit to be a seal of approval?
BIN lADEN, Mugabe, Members of the mafia are all very religious persons
How to raise more doubts as possible and make conspiracy theorists happy
- present pictures so badly photoshopped that the deception is immediately discovered;
- Get rid in unseemly haste of decisive evidence in favor of one's own statements with fanciful reasons;
-Refusing to show photos or videos on the grounds of ludicrous excuses;
- Give a first version of the facts (a) then amend it (a1), then a completely different version (b) finally, yet another version (c);
- Diffuse material insignificant or already seen as a sop.
The CIA has followed these instructions to the letter, apparently.
- Get rid in unseemly haste of decisive evidence in favor of one's own statements with fanciful reasons;
-Refusing to show photos or videos on the grounds of ludicrous excuses;
- Give a first version of the facts (a) then amend it (a1), then a completely different version (b) finally, yet another version (c);
- Diffuse material insignificant or already seen as a sop.
The CIA has followed these instructions to the letter, apparently.
Sunday, May 8, 2011
Sailing the Titan Seas
http://www.physorg.com/news/2011-05-titan-seas.html
Sunlight reflects off a Titan lake in this image captured by NASA's Cassini spacecraft. The Titan Mare Explorer (TiME), a candidate for NASA's next Discovery-class mission, would perform the first direct inspection of an ocean environment beyond Earth by landing in, and floating on, a large methane-ethane sea on the cloudy, complex moon of Saturn. Image Credit:NASA
(PhysOrg.com) -- The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., is managing a project to explore the organic seas of Saturn's moon Titan, one of three proposals selected by NASA this week as candidates for the agency's next Discovery Program mission.
Ads by Google
New sCMOS Camera - The first true scientific CMOS camera available now from Andor. - www.andor.com/scmos
The Titan Mare Explorer, or TiME, would perform the first direct inspection of an ocean environment beyond Earth by landing in, and floating on, a large methane-ethane sea on the cloudy, complex moon. The mission would be led by principal investigator Ellen Stofan of Proxemy Research Inc. in Gaithersburg, Md. Lockheed Martin in Denver would build the TiME capsule, with scientific instruments provided by APL, Goddard Space Flight Center in Greenbelt, Md., and Malin Space Science Systems in San Diego.
Also selected were a NASA Jet Propulsion Laboratory lander that would study the Martian interior, and a NASA Goddard project to land on a comet multiple times and observe its interaction with the sun. Chosen from 28 full-mission proposals submitted to NASA last summer, each investigation team now receives $3 million to develop a detailed concept study. After another review of those studies in 2012, NASA will select one to develop for launch. The selected mission will be cost-capped at $425 million, not including launch vehicle funding.
APL also has a role on the NASA Goddard mission team, to provide a high-resolution telescopic camera for the "Comet Hopper" spacecraft.
"NASA's comment on the Discovery selection was, 'if ever there was a time to demonstrate being able to think differently, this is it,'" says John Sommerer, head of APL's Space Department. "It's 'common knowledge' that outer-planets missions are billion-dollar operations, but our team proposed a lander on Titan in the low-cost Discovery mission series. Coming off the success of both the MESSENGER mission to Mercury and the New Horizons mission now on its way to Pluto, it's clear that APL has met the challenge to think differently."
The TiME capsule would launch in 2016 and reach Titan in 2023, parachuting onto the moon's second-largest northern sea, the Ligeia Mare. For 96 days the capsule would study the composition and behavior of the sea and its interaction with Titan's weather and climate. TiME would also seek evidence of the complex organic chemistry that may be active on Titan today, and that may be similar to processes that led to the development of life on the early Earth.
Provided by Johns Hopkins University (news : web)
Saturday, May 7, 2011
Friday, May 6, 2011
Thursday, May 5, 2011
Tell us the truth, already!
I'm glad the fiend Bin Laden is no more.
I'd have however gladly seen Bin Laden tried before an International Court like that of Aja. Why wasn't he caught alive? Why this hasty disposal of the body and this "we can't show you the photos, they're too horrible!" Pleeez! Give us a break!
If they wanted the conspiracy theorists to suspect foul play, they've given them plenty to ruminate upon.
Think of it:
India, a century ago. I say to my friemds I've captured and killed a much sought after man-eating tiger. "Show it to you? But I threw it in the river! A Photo? Nooo, they're too ugly, you'd be shocked! Doubt? Why should you?"
Why, indeed!
However, if the face of Bin Laden was blasted by a gun, well, I suppose there was little to see for reconnaissance,and would have been a nasty sight, for sure. Maybe this is the explanation.
I'd have however gladly seen Bin Laden tried before an International Court like that of Aja. Why wasn't he caught alive? Why this hasty disposal of the body and this "we can't show you the photos, they're too horrible!" Pleeez! Give us a break!
If they wanted the conspiracy theorists to suspect foul play, they've given them plenty to ruminate upon.
Think of it:
India, a century ago. I say to my friemds I've captured and killed a much sought after man-eating tiger. "Show it to you? But I threw it in the river! A Photo? Nooo, they're too ugly, you'd be shocked! Doubt? Why should you?"
Why, indeed!
However, if the face of Bin Laden was blasted by a gun, well, I suppose there was little to see for reconnaissance,and would have been a nasty sight, for sure. Maybe this is the explanation.
Wednesday, May 4, 2011
Tuesday, May 3, 2011
Monday, May 2, 2011
Modernity: I'm all for it
I'll bet: the armies of the night, the haters of modernity does not rejoice at the end of Bin
Laden
Anti-modernist counted on that fiend to sweep away the hated (by them) modernity.
Religious fundamentalists, nostalgic fascists who yearn for the apocalyptic end of the world
cultural relativists who admire the "values" of the religions that hang homosexuals and
stone and oppress women.. Those who want to return to the Middle Ages dreaming of a role
of directors to the dictator, who will reward them with privileges denied to ordinary mortals.
Anti-modernist as so called christian Right, friends of Gingrich, Palin, gay haters and deniers of the separation between Church and State.
These anti-modernist take advantage of all the comforts of the modern world, and if they get sick
I doubt seriously that they'll recur to a holy man or rely on the power of
prayers: I think that they'll use the most advanced discoveries of modern medicine, as
Mother Teresa did. They take advantage of of the Web to spread their word obscurantist
enemy of human rights, but call upon those rights whenever they consider that their right to
spread obscurantism, homophobia and anti-scientism is disputed ... and call simple criticism persecution.
I have no sympathy for the anti-modernist, people who bite the hand that feeds them, and that will probably be
licking her feet kicking them should their dire predictions ever come true.
Modernity is not perfect, but the anti-modernist world is much worse.
Laden
Anti-modernist counted on that fiend to sweep away the hated (by them) modernity.
Religious fundamentalists, nostalgic fascists who yearn for the apocalyptic end of the world
cultural relativists who admire the "values" of the religions that hang homosexuals and
stone and oppress women.. Those who want to return to the Middle Ages dreaming of a role
of directors to the dictator, who will reward them with privileges denied to ordinary mortals.
Anti-modernist as so called christian Right, friends of Gingrich, Palin, gay haters and deniers of the separation between Church and State.
These anti-modernist take advantage of all the comforts of the modern world, and if they get sick
I doubt seriously that they'll recur to a holy man or rely on the power of
prayers: I think that they'll use the most advanced discoveries of modern medicine, as
Mother Teresa did. They take advantage of of the Web to spread their word obscurantist
enemy of human rights, but call upon those rights whenever they consider that their right to
spread obscurantism, homophobia and anti-scientism is disputed ... and call simple criticism persecution.
I have no sympathy for the anti-modernist, people who bite the hand that feeds them, and that will probably be
licking her feet kicking them should their dire predictions ever come true.
Modernity is not perfect, but the anti-modernist world is much worse.
Good Riddance!
The criminal against humanity Osama bin Laden is dead!
The innocent victims he made worldwide, beginning with the Twin Towers victims, are avenged!
MAY HE ROT IN HELL
Subscribe to:
Posts (Atom)