Official "Science News" Thread

[ewmayer]

@^^

Hey, at least Mr. Ragozzine managed to avoid the pompous and overused "new paradigm".

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At the suggestion my nephew, I am currently watching the season 1 DVD set of the critically acclaimed cable series Breaking bad. An interesting bit of "drug history you may not have known" related to Methamphetamine:

One of the earliest uses of methamphetamine was during World War II, when it was used by Axis and Allied forces.[95] The company Temmler produced methamphetamine under the trademark Pervitin and so did the German and Finnish militaries. It was also dubbed "Pilot's chocolate" or "Pilot's salt".[96] It was widely distributed across rank and division, from elite forces to tank crews and aircraft personnel, with many millions of tablets being distributed throughout the war.[97] More than 35 million three-milligram doses of Pervitin and the closely related Isophan were manufactured for the German army and air force between April and July 1940.[98] From 1942 until his death in 1945, Adolf Hitler may have been given intravenous injections of methamphetamine by his personal physician Theodor Morell. It is possible that it was used to treat Hitler's speculated Parkinson's disease, or that his Parkinson-like symptoms that developed from 1940 onwards resulted from using methamphetamine.[99] In Japan, methamphetamine was sold under the registered trademark of Philopon (ヒロポン[100] hiropon[101]) by Dainippon Pharmaceuticals (present-day Dainippon Sumitomo Pharma) for civilian and military use. As with the rest of the world at the time, the side effects of methamphetamine were not well studied, and regulation was not seen as necessary. In the 1940s and 1950s the drug was widely administered to Japanese industrial workers to increase their productivity.[102]

Methamphetamine and amphetamine were given to Allied bomber pilots during World War II to sustain them by fighting off fatigue and enhancing focus during long flights. The experiment failed because soldiers became agitated, could not channel their aggression and showed impaired judgment.[93] Rather, dextroamphetamine (Dexedrine) became the drug of choice for American bomber pilots, being used on a voluntary basis by roughly half of the U.S. Air Force pilots during the Persian Gulf War, a practice which came under some media scrutiny in 2003 after a mistaken attack on Canadian troops.[103]

[firejuggler]

HIggs Boson and gravity

[Dubslow]

Earth sized planet discovered in Alpha Centauri B (4.3 ly, closest system to our own) (too close/hot though for life)

Alpha Centauri Bb zips around its star every 3.2 days, orbiting at a distance of just 3.6 million miles (6 million kilometers). For comparison, Earth orbits about 93 million miles, or 150 million km, from the sun.

The research team, led by Xavier Dumusque of Geneva Observatory and the University of Porto in Portugal, spotted Alpha Centauri Bb using an instrument called the High Accuracy Radial velocity Planet Searcher, or HARPS.
HARPS is part of the European Southern Observatory's 11.8-foot (3.6 meters) telescope at the La Silla Observatory in Chile. The instrument allows astronomers to pick up the tiny gravitational wobbles an orbiting planet induces in its parent star.

In the case of Alpha Centauri Bb, these wobbles are very tiny indeed; the planet causes its star to move back and forth at no more than 1.1 mph (1.8 kph). It took more than 450 HARPS measurements spread out over four years of observing to detect the planet's signal, Dumusque said.
"It’s an extraordinary discovery, and it has pushed our technique to the limit," he said in a statement.

To be published tomorrow in Nature.

By the way, as some may have inferred, I can offer access on request to any scholarly article anyone wants. (That includes this one or anything in the thread or anything at all.)

[Brian-E]

Originally Posted by Dubslow

Earth sized planet discovered in Alpha Centauri B (4.3 ly, closest system to our own) (too close/hot though for life)

This article, and others concerning the discovery, speculate about the possible existence of planets in the "habitable zone" of Alpha Centauri. However I fail to see how a planetary orbit can exist in any habitable zone of this system. The two main component stars are very close together, at a distance comparable to that between the solar system's giant planets and the sun, which means that any planets in stable orbits must either (a) orbit just one of the component stars at too close a distance for life to exist, as is true of the newly discovered planet, or (b) orbit the whole two-star system (ignoring the tiny and distant proxima centauri which won't be gravitationally important) at a distance much too large to support life.

Have I missed something?

EDIT: Let's try and answer my own question. Have I missed the possibility of a planet orbiting one of the components in a habitable zone so that the plane of its orbit is very different from, nearly orthogonal to, that of the orbit of the two component stars? Would that be necessary, and if so, doesn't it require shaking up some of the theories of solar system formation?

[axn]

<WAG>
B is much dimmer than our sun. So maybe something like the orbit of mercury might be habitable?

Another possibility is that a planet is orbiting both the stars, and _part_ of the orbit is in the habitable zone?
</WAG>

Hmm...

Originally Posted by From the all-knowing one

To be in the star's habitable zone, any suspected Earth-like planet around Alpha Centauri A would have to be placed about 1.25 AU away – about halfway between the distances of Earth's orbit and Mars's orbit in the Solar System – so as to have similar planetary temperatures and conditions for liquid water to exist. For the slightly less luminous and cooler Alpha Centauri B, this distance would be closer to its star at about 0.7 AU (100 million km), being about the distance that Venus is from the Sun.

[Dubslow]

Originally Posted by Brian-E

This article, and others concerning the discovery, speculate about the possible existence of planets in the "habitable zone" of Alpha Centauri. However I fail to see how a planetary orbit can exist in any habitable zone of this system. The two main component stars are very close together, at a distance comparable to that between the solar system's giant planets and the sun, which means that any planets in stable orbits must either (a) orbit just one of the component stars at too close a distance for life to exist, as is true of the newly discovered planet, or (b) orbit the whole two-star system (ignoring the tiny and distant proxima centauri which won't be gravitationally important) at a distance much too large to support life.

Have I missed something?

To answer your question:

Originally Posted by The all-knowing one

With the orbital period of 79.91 years,[39] the A and B components of this binary star can approach each other to 11.2 astronomical units, equivalent to 1.67 billion km or about the mean distance between the Sun and Saturn, or may recede as far as 35.6 AU (5.3 billion km—approximately the distance from the Sun to Pluto).[39][49] This is a consequence of the binary's moderate orbital eccentricity e = 0.5179.

And to add in axn's quote:

Originally Posted by The all-knowing one

To be in the star's habitable zone, any suspected Earth-like planet around Alpha Centauri A would have to be placed about 1.25 AU away – about halfway between the distances of Earth's orbit and Mars's orbit in the Solar System – so as to have similar planetary temperatures and conditions for liquid water to exist. For the slightly less luminous and cooler Alpha Centauri B, this distance would be closer to its star at about 0.7 AU (100 million km), being about the distance that Venus is from the Sun.

So the stars don't get closer than about 10 times the radius of a habitable orbit. That's perfectly reasonable. (It wouldn't be anything like a circular orbit for sure, but I'm certain it's possible.)
Edit: Here's another semi-relevant quote:

Originally Posted by The omniscitor

In 2009, computer simulations (then, unaware of the close-in planet Bb) showed that a planet might have been able to form near the inner edge of Alpha Centauri B's habitable zone, which extends from 0.5 to 0.9 AU from the star. Certain special assumptions, such as considering that Alpha Centauri A and B may have initially formed with a wider separation and later moved closer to each other (as might be possible if they formed in a dense star cluster) would permit an accretion-friendly environment farther from the star.[89] Bodies around A would be able to orbit at slightly farther distances due to A's stronger gravity. In addition, the lack of any brown dwarfs or gas giants in close orbits around A or B make the likelihood of terrestrial planets greater than otherwise.[82] Theoretical studies on the detectability via radial velocity analysis have shown that a dedicated campaign of high-cadence observations with a 1–m class telescope can reliably detect a hypothetical planet of 1.8 Earth masses in the habitable zone of B within three years.[90]

[Brian-E]

Thanks axn and Dubslow.

I was limiting my vision to planetary orbits which are almost circular and in the habitable zone at all points on the orbit, although I did not explicitly state that. If the habitable zone of a sun-like star is less narrow than some theories suggest, then I can see that Alpha Centauri need not be ruled out as home to a life supporting planet.

[xilman]

Originally Posted by Brian-E

Thanks axn and Dubslow.

I was limiting my vision to planetary orbits which are almost circular and in the habitable zone at all points on the orbit, although I did not explicitly state that. If the habitable zone of a sun-like star is less narrow than some theories suggest, then I can see that Alpha Centauri need not be ruled out as home to a life supporting planet.

It's life Jim, but not as we know it.

For instance, I see no reason at all why water-based life couldn't be widespread in Jovian planets throughout the universe, and I include Jupiter and Saturn as candidates. In each of the latter planets there are (very large!) regions where humans could survive protected only by a face mask, oxygen supply and a hot air balloon. That is, where the pressure is in the range 0.5 to 10 atmospheres and the temperature is 0-30 Celsius. The face mask is to keep the ammonia and other such nasties out of your eyes.

If you don't require a (reasonably pure) liquid water environment for life all bets are off. A super-earth with a liquid NH₃/H₂O ocean and an adequate greenhouse effect (almost inevitable IMO) could be located half way to Jupiter and still be suitable for life. The ocean could have a temperature at -30C and still be liquid; several atmospheres pressure of a NH₃ and H₂O mix would provide substantial greenhouse warming.

[ewmayer]

Spectacular meteoric fireball yesterday evening here in the SF Bay area - I just missed it, was out for ~20 minutes around 7:30 last night, had my eyes on the sky to watch a spectacular crescent-moonset over the coastal mountains, got inside about 7:40 pm, just 5 minutes before the fireball. According to the news last night the meteorite was likely part of the Orionid shower, the main shower associated with comet Halley, which due to their high average earth-crossing speed produce disproportionately many flash-bang-style fireballs. One astronomer noted that last night's fireball may have needed only a marble-sized meteor to produce it.

Today, the story has changed, and it is deemed unlikely that the meteor was an Orionid. "You can't dust for cometary tails," or some such police-nonsense excuse. By way of compensation, the estimated size of the object has been upgraded from a mere marble to a much-more-impressive "size of a microwave to a small car". (Or perhaps that last bit is a typo and they really meant "small cat".)

[xilman]

Originally Posted by ewmayer

Spectacular meteoric fireball yesterday evening here in the SF Bay area

We got one too!

Perhaps they were Orionids after all.

[ewmayer]

Here is a grainy video of the Bay Area meteor: The fireball is the blob moving left-to-right at top of the image, not sure what the comet-looking (non-moving) streak of light below it is.

http://www.youtube.com/embed/S0PEMOlhAdE

While there is not yet any conclusive evidence of fragments surviving atmospheric entry, the estimated size indicates good odds of such, so amateur meteorite hunters are scouring the east bay hills as I write this.