Quantumaniac

Weird Spiral Features Found on Mars

Strange coiling spiral patterns have been found on Mars surface by a graduate student who was doing what many of us enjoy: looking through the high-resolution images from the HiRISE camera on the Mars Reconnaissance Orbiter. Similar features have been seen on Earth, but this is the first time they have been identified on Mars. However, on Mars, these features, called lava coils, are supersized. “On Mars the largest lava coil is 30 meters across – that’s 100 feet,” said Andrew Ryan from Arizona State University. “That’s bigger than any known lava coils on Earth.”

The lava coils resemble snail or nautilus shells. Ryan has found about 269 of these lava coils just in one region on Mars, Cerberus Palus. 174 of them swirl in a clockwise-in orientation, 43 are counterclockwise, and 52 of the features remain unclassified due to resolution limits.

On Earth, lava coils can be found on the Big Island of Hawaii, mainly on the surface of ropey pahoehoe lava flows. They usually form along slow-moving shear zones in a flow; for example, along the margins of a small channel, and the direction of the flow can be determined from a lava coil.

Math peeps - do you see any relation to a Fibonacci spiral? I’m interested to see how this possible connection might be handled. 

Read more. 

How Much Does Fire Weigh? 

Question: Since fire is a plasma, and plasma is a state of matter, and matter is defined as anything that has mass, would that then mean that fire has mass and weight to it? If so, is there a way to measure its weight? How much space would, say, a pound of fire take up?

Answer: It weighs more than nothing, but if you’re at the bottom of a pillar of fire, being crushed should be your second concern

Fires, putting aside details about plasma and chemicals or whatever, is just hot air.  For a given pressure the ideal gas law says that the density of a gas is inversely proportional to temperature, in Kelvin.  You can use this fact, the temperature and density of air (300°K 1.3 kg/m³), and the temperature of your average run-of-the-mill open flame (about 1300°K) to find the density of fire. For most “everyday” fires, the density of the gas in the flame will be about 1/4 the density of air.  So, since air (at sea level) weighs about 1.3 kg per cubic meter (1.3 grams per liter), fire weighs about 0.3 kg per cubic meter.

One pound of ordinary fire, here on Earth near sea level, would take up a cube about 1.2 meters to a side.  The reason that fires always flow upward is that its density is lower than air.  So, fire rises in air for the same reason that bubbles rise in water: it’s buoyant.  Enterprising individuals sometimes even take advantage of that fact.

If you were on a planet with no air at all, fire would fall to the ground instead of rise because, like all matter, it’s pulled by gravity.  Also, it would be hard to keep the fire going (what with there being no air).

(Source: askamathematician.com)

Symmetree

The Worst Thing Ever

Closing In On Dark Matter

When physicists and mathematicians want to get an idea into circulation before going through all the hoo-hah of peer-reviewed publication, they often post a paper on the arXiv server, where anyone who is curious can go and read it. Some arXiv papers turn out to be important, but much evaporates on closer inspection. Judging whether a new arXiv paper is one or the other can be extremely difficult. That is certainly the case with physicist Christoph Weniger’s paper, “A Tentative Gamma-Ray Line from Dark Matter Annihilation at the Fermi Large Area Telescope,” posted on April 12, on dark matter.

Dark matter, invisible and undetectable, makes up more than a quarter of the universe and has been an enigma to physicists and astronomers for more than a century. While physicists can’t look at dark matter directly, they can try to tell-tale trails that dark matter was present. Weniger has produced an analysis of data that—if it holds up—is a major step forward in explaining dark matter, and might provide the first unambiguous evidence of what this mysterious and elusive substance is.

Of course, we’ve heard dramatic claims like this before that didn’t pan out—and it’s certainly possible this one won’t either. We won’t know which way it goes until other scientists digest the analysis and weigh in, which could take months. And even so, it may take years before the findings are confirmed. In the meantime, it’s worth having a look at this latest experimental claim, if only to see how an outsider —a theorist unaffiliated with an experimental collaboration— occasionally tries to make a splash in the big collaboration world of physics.

The outsider, of course, is Weniger. A post-doc at the Max-Planck Institute of Physics, he is not a member of the collaboration that works on the Fermi Large Area Telescope (the collaboration goes by the acronym Fermi-LAT). However, Fermi-LAT makes its data publicly available, which allowed Weniger to use it for his investigation. In fact, his analysis goes over ground that researchers collaborating on the Fermi-LAT project have already trod. When they analyzed their data in previous years, the Fermi-LAT researchers found no strong evidence for dark matter. Weniger, however, wasn’t convinced. He and a few colleagues opted to re-crunch the Fermi-LAT data and in March, posted hints of dark matter that they had spotted. Weniger’s April 12 paper goes a step further, suggesting he’s spotted an even stronger signal at a specific energy.

Weniger’s analysis relies on a theory that predicts that when particles of dark matter meet, they will annihilate one another and create photons. In principal, you should be able to spot these photons in the form of high-energy gamma rays. Since the Large Area Telescope was built to study gamma rays, it’s an ideal instrument for this kind of search.

Weniger analyzed 43 months of data, which yielded strong evidence for a gamma ray source in the outskirts of the galaxy—a region called the galactic halo—which is exactly where theorists would predict you could find dark energy annihilations. Specifically, he’s claimed to spot the candidate gamma rays at 130 billion electron volts. For those of you keen on the statistical details, he’s claiming it with as much as 4.6 sigma certainty—which is to say, a high degree of certainty. For context: In current particle physics, evidence for the Higgs boson would be accepted as a discovery at 5 sigma certainty, so 4.6 is pretty good. That said, when he incorporates the necessary statistics for his targeted search and sample size, his results drop to a 3.5 sigma certainty, barely strong enough for publication.

What makes Weniger think that he got it right while the insiders at Fermi-LAT got it wrong? His is the first to include a full 43 months of data. Previous Fermi-LAT collaboration publications, such as results published in 2010, are limited to just 11 months.In addition, to updating the dataset, Weniger has developed his own algorithms for the dark matter search, which he believes do a better job understanding the region of the galaxy where dark matter is alleged to be. This improves his chances of distinguishing the sought out gamma rays from other galactic events.

But before we pop open the champagne, there are several important caveats. As Weniger himself acknowledges, several more years of data will be needed before it’s clear whether what he thinks he’s seen is real. In addition, because Weniger isn’t a member of the team that gathers data at Fermi-LAT, it’s possible he doesn’t entirely understand how the technology involved in detecting and collecting the data may affect the data. This is something that only collaborators are likely to have studied with enough care to correct for in their analysis. The paper could amount to nothing more than another dark matter dead end.

Things might get interesting if the Journal of Cosmology and Astroparticle Physics, to which Weniger is submitting this paper, opts to publish. That stamp of approval would set Weniger’s work above a great many other arXived efforts. Another development to watch for is a response from the folks on the Fermi collaboration. They know this data better than anyone, and if there’s something to be learned from Weniger’s approach, they’ll want to take it seriously. If nothing else, this is one more in a string of recent examples that shows how we are closing in on dark matter. For now, we watch and wait.

(Source: blogs.scientificamerican.com)

Question / Answer / Knowledge

Physics Clock

• Newton became a professor of mathematics at only 26.
• Newton practiced Alchemy. 
• Newton was elected as a member of parliment. His membership lasted only a year.
• Newton earned the title of Warden of the Royal Mint.
• Newton oversaw the recoinage of the whole country.
• Newton was knighted because of his political activites.
• He was named after his father who died three months before Isaac was born.
• Isaac was born early. He was so small he could have put him in a quart jug.
• Isaac’s father could hardly write his name.
• Isaac was one of the worst in his class until a bully at school kicked him. Isaac challenged him to a fight even though he was smaller. He won. That wasn’t enough for him, he decided to be better than the bully at school as well.
• Isaac liked to draw, his room was even colored on the ceilings and walls.
• Newton was born on Christmas.

Fullerenes and Buckyballs

Despite the seemingly complex name, a fullerene is nothing more than a molecule composed entirely of carbon. That’s all! Fullerenes can come in the shape of a hollow sphere, ellipsoid or tube. When a fullerene is spherical, they are known as buckyballs - and when cylindrical they are called carbon nanotubes or can be affectionately called buckytubes. Fullerenes are similar in structure to graphite, which is composed of stacked graphene sheets of linked hexagonal rings; but they may also contain pentagonal (or sometimes heptagonal) rings.

The first fullerene to be discovered, buckminsterfullerene (C₆₀), was prepared in 1985 by Richard Smalley, Robert Curl, James Heath, Sean O’Brien, and Harold Kroto at Rice University. The name was an homage to Buckminster Fuller, whose geodesic domes it resembles. The structure was also identified some five years earlier by Sumio Iijima, from an electron microscope image, where it formed the core of a “bucky onion.” Fullerenes have since been found to occur in nature. More recently, fullerenes have been detected in outer space. According to astronomer Letizia Stanghellini, “It’s possible that buckyballs from outer space provided seeds for life on Earth.”

The discovery of fullerenes greatly expanded the number of known carbon allotropes, which until recently were limited to graphite, diamond, andamorphous carbon such as soot and charcoal. Buckyballs and buckytubes have been the subject of intense research, both for their unique chemistry and for their technological applications, especially in materials science, electronics, and nanotechnology.