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Missery ain't just nuttin' but rednecks and methheads... a scientist at UCM(Go Mules!) recently found the largest known prime number. Get out a pen and write it down...
January 7, 2016 — GIMPS celebrated its 20th anniversary with the discovery of the largest known prime number, 274,207,281-1. Curtis Cooper, one of many thousands of GIMPS volunteers, used one of his university's computers to make the find. The prime number, also known as M74207281, is calculated by multiplying together 74,207,281 twos then subtracting one. It has 22,338,618 digits -- almost 5 million digits longer than the previous record prime number.
While prime numbers are important for cryptography, this prime is too large to currently be of practical value. However, the search itself does have several practical benefits. Historically, searching for Mersenne primes has been used as a test for computer hardware. Earlier this month, GIMPS' prime95 software and members of a German computing community uncovered a flaw in Intel's latest Skylake CPUs. Prime95 has also discovered hardware problems in many individual's PCs.
To prove there were no errors in the prime discovery process, the prime was independently verified using both different programs and different hardware. Andreas Hoglund and David Stanfill each verified the prime using the CUDALucas software running on NVidia Titan GPUs. David Stanfill also verified using ClLucas on an AMD Fury GPU. Finally, Serge Batalov ran Ernst Mayer's MLucas software on a 18-core server to verify the prime.
Dr. Cooper is a professor at the University of Central Missouri. This is the fourth record prime for Dr. Cooper and his university. Their first record prime was discovered in 2005, eclipsed by their second record in 2006. Dr. Cooper lost the record in 2008, but reclaimed it in 2013, and improved the record with this new prime. The primality proof took a month of computing on a PC with an Intel I7-4790 CPU. Dr. Cooper and the University of Central Missouri is the largest contributor of CPU time to the GIMPS project. The discovery is eligible for a $3,000 GIMPS research discovery award.
While Dr. Cooper's computer found the record prime, the discovery would not have been possible without all the GIMPS volunteers that sifted through numerous non-prime candidates. GIMPS founder George Woltman, PrimeNet creator Scott Kurowski, Primenet administrator Aaron Blosser, thank and congratulate all the GIMPS members that made this discovery possible. To recognize all those that contributed to this discovery, official credit goes to Cooper, Woltman, Kurowski, Blosser, et al.
The new prime number is a member of a special class of extremely rare prime numbers known as Mersenne primes. Mersenne primes were named for the French monk Marin Mersenne, who studied these numbers more than 350 years ago. There are only 49 known Mersenne primes. GIMPS, founded in 1996, has discovered the last 15 Mersenne primes. Volunteers download a free program to search for these primes with a cash award offered to anyone lucky enough to find a new prime. Prof. Chris Caldwell maintains an authoritative web site on the largest known primes as well an excellent history of Mersenne primes.
Interestingly, Dr. Cooper's computer reported the prime to the server on September 17, 2015. However, a bug prevented the email notification from being sent. The new prime remained unnoticed until routine database maintenance took place months later. The official discovery date is the day a human took note of the result. This is in keeping with tradition as M4253 is considered never to have been the largest known prime number because Alexander Hurwitz in 1961 read his computer printout backwards and saw M4423 was prime seconds before seeing that M4253 was also prime. [Reply]
The waterbears were retrieved from frozen moss sample collected in Antarctica in 1983
Researchers have successfully revived microscopic creatures that had been kept frozen for 30 years.
Tardigrades, also known as waterbears or moss piglets, are tiny water-dwelling organisms. They're segmented, with eight legs, and measure 1mm in length.
Scientists at at Japan's National Institute of Polar Research retrieved the creatures from a frozen moss sample collected in Antarctica in 1983. The sample had been stored at −20 °C for just over three decades.
Two waterbears were resuscitated. One of them died after 20 days, but the other went on to successfully reproduce with a third specimen hatched from a frozen egg.
It laid 19 eggs, of which 14 hatched successfully.
Found throughout the world, tardigrades can survive extreme pressure, such as deep underwater, and can even live in the vacuum of space for several days.
When they're frozen, the creatures enter a state called cryptobiosis, in which their metabolic processes shut down, and they show no visible signs of life.
"The present study extends the known length of long-term survival in tardigrade species considerably," said researchers.
The previous survival record for adult tardigrades under frozen conditions was eight years, and a much earlier study had suggested that the upper limit for survival under normal atmospheric oxygen conditions was about 10 years.
"We want to unravel the mechanism for long-term survival by looking into damage to tardigrades' DNA and their ability to repair it," said research lead Megumu Tsujimoto.
National Institute of Polar Research now plans to work on examining damage to the water bear's genes and its recovery functions to achieve a better understanding of its long-term survival mechanism.
Hardy though the tardigrades in this study undoubtedly were, they didn't beat the record for survival in a frozen state: that's currently held by a nematode worm that managed nearly 39 years. [Reply]
It is lazy speech, but things that are in solid state (frozen) on other planets, that are normally liquid or gaseous (methane, ammonia) here on earth are lumped together as 'ice' "The icy planets", etc. At some point later, this lazy speech causes someone to have to specify 'what kind of ice' as water ice. [Reply]
So there's a special press conference being held today. Rumor has it that they may be announcing the detection of gravitational waves. Which would be the biggest discovery in a long time. Gravitational waves were predicted by Einstein, and are a part of his general theory of relativity. However, this wouldn't be the first time someone has claimed to discover gravitational waves. I remain very skeptical.
The press conference is coming up shortly at 9:30am:
LIGO the Laser Interferometer Gravitational-Wave Observatory may announce the detection of gravitational waves tomorrow at 10:30AM Eastern time. I will watch it and live tweet it. The question of the day for most normal people will be... What are gravitational waves?
The short answer
In Einstein's theory of gravity called General Relativity mass causes space time to curve, meaning the shortest distance between two points in space time is not a straight line near a massive object. Gravitational waves are changes in the shortest distance between two points which move like waves. These are different than other waves though. They are radiated when two masses interact, or one mass changes shape. They are so slight that it takes binary pairs of neutron stars or pairs of black holes to generate effects we can practically try to detect with current technology.
The shortest long answer to precisely what LIGO has been looking for.
LIGO uses an interferometer to measure tiny changes in the length of a beams of light several kilometers long. Light is sent down each arm then recombined to cause a pattern of light and dark fringes. A similar experiment performed in the early 1900's backed Einstein's Special Relativity theory ( the one that gave us but does not include gravity).
The key equation of General Relativity is
the key quantity in that equation is it is called the metric. A metric defines distance between points in space time. T in that equation is called the stress-energy tensor, in the text I will use a bold capital letter when I'm talking about a tensor. The quantities you see there which have two Greek subscripts are called Tensors of rank two. The best visual of a tensor at work that you see every day would be the way concrete expands when warmed and contracts when cold. Another example consider the way a block of clay changes shape in multiple directions but how much it expands on one axis effects how it can expand on another axis.
When pairs of neutron stars or pairs of black holes interact they slowly spiral into each other. All the time loosing energy as the pair radiates off gravitational waves.
It takes the stress energy tensor T caused when masses several times that of our sun interact to cause tiny changes in the metric g which interferometers like those used by LIGO could pick up.
Noise from local sources, vibrations, ground movements and tremors, etc can cause a false positive. This is why they used more than one interferometer linked over a great distance. If both instruments detect an event then it is likely to be a real signal and not just noise.
Even if the collaboration thinks they have a detection the thing scientist will look at is the noise profile and consider how strong the signal is compared to the noise. Collaborations like LIGO have thought they detected something, and held a press conference before. We'll see. [Reply]
The waves were produced during the final fraction of a second of the merger of two black holes 1.3 billion years ago. For a brief fraction of a second, it was producing more energy power than the rest of the visible Universe combined.
One Scientist put it at 50 times the power of all the suns in the universe combined. Whoa. [Reply]
