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A new model for human evolution asserts that modern Homo sapiens stemmed from multiple genetically diverse populations across Africa rather than a single ancestral population. This conclusion was reached after researchers analyzed genetic data from present-day African populations, including 44 newly sequenced genomes from the Nama group of southern Africa. The research suggests that the earliest detectable split in early human populations occurred between 120,000 to 135,000 years ago, after long periods of genetic intermixing, and that subsequent migrations created a weakly structured genetic stem. Contrary to some previous models, this research implies that contributions from archaic hominins were unlikely...

[A]n unseen ‘mirror world’ of particles that interacts with our world only via gravity might be the key to solving a major puzzle in cosmology today – the Hubble constant problem. The Hubble constant is the current rate of expansion of the universe. Predictions for this rate — from cosmology’s standard model — are significantly slower than the rate found by our most precise local measurements. This discrepancy is one that many cosmologists have been attempting to solve by changing our current cosmological model. The challenge is to do so without ruining the agreement between standard model predictions and many...

These galaxies are selected from a Hubble Space Telescope program to measure the expansion rate of the universe, called the Hubble constant. The value is calculated by comparing the galaxies' distances to the apparent rate of recession away from Earth (due to the relativistic effects of expanding space). By comparing the apparent brightnesses of the galaxies' red giant stars with nearby red giants, whose distances were measured with other methods, astronomers are able to determine how far away each of the host galaxies are. This is possible because red giants are reliable milepost markers because they all reach the same...

Nearly 40 years after it was proposed, mathematicians have settled one of the most profound questions in the study of general relativity. In a paper posted online last fall, mathematicians Mihalis Dafermos and Jonathan Luk have proven that the strong cosmic censorship conjecture, which concerns the strange inner workings of black holes, is false.“I personally view this work as a tremendous achievement — a qualitative jump in our understanding of general relativity,” emailed Igor Rodnianski, a mathematician at Princeton University.The strong cosmic censorship conjecture was proposed in 1979 by the influential physicist Roger Penrose. It was meant as a...

Last year’s discovery of the Higgs boson was thought to answer a number of questions regarding how particles derive their mass. Now, however, it seems the discovery of the elusive particle is raising more questions than answers. Physicists at King’s College in London now say they have recreated conditions for the Big Bang now with the information from the discovery of the Higgs boson, and they report that the universe should have expanded too quickly and collapsed.

Physicists Say Can Find No Sign of 'God Particle' LONDON (Reuters) - After years of searching and months of sifting through data, scientists have still not found the elusive sub-atomic particle that could help to unravel the secrets of the universe, a science magazine said on Wednesday.The Higgs boson, the missing link which could explain why matter has mass and other fundamental laws of particle physics, is still missing -- and physicists fear it may not exist.``It's more likely than not that there is no Higgs,'' John Swain, of Northeastern University in Boston, told New Scientist magazine.Scientists have been searching ...

"Recent results from the Dzero experiment at the Tevatron particle accelerator suggest that those looking for a single Higgs boson particle should be looking for five particles, and the data gathered may point to new laws beyond the Standard Model. 'The DZero results showed much more significant "asymmetry" of matter and anti-matter — beyond what could be explained by the Standard Model. Bogdan Dobrescu, Adam Martin and Patrick J Fox from Fermilab say this large asymmetry effect can be accounted for by the existence of multiple Higgs bosons. They say the data point to five Higgs bosons with similar masses...

From the masses and interactions of other particles that we know exist, physicists calculated that the Higgs is most likely to have a mass (or energy) of around 80 gigaelectronvolts (GeV). If particle accelerators smash particles together at that energy or higher, it should be possible to make one. This is what members of the Electroweak Working Group at CERN were doing for the 5 years until LEP (the Large Electron Positron Collider) closed down last year. Since then they've been sifting through the data they gathered--and found nothing. They rule out most possible masses for the Higgs, including the...

DENVER — The discovery of the Higgs boson is real. But physicists are cagey about whether the new particle they've found will fit their predictions or not. So far, the data suggest that the Higgs, the particle thought to explain how other particles get their mass, is not presenting any surprises, physicists said here Saturday at the April meeting of the American Physical Society. But that doesn't mean that it won't in the future — or that there might not be other Higgs bosons lurking out there. "There's a large number of theoretical models that predict, actually, that this Higgs...

The discovery of the Higgs boson is real. But physicists are cagey about whether the new particle they've found will fit their predictions or not. So far, the data suggest that the Higgs, the particle thought to explain how other particles get their mass, is not presenting any surprises, physicists said here today (April 13) at the April meeting of the American Physical Society. But that doesn't mean that it won't in the future — or that there might not be other Higgs bosons lurking out there. "There's a large number of theoretical models that predict, actually, that this Higgs...

The University of Maryland physicist believes the delay could have been because the light was in fact slowed as it travelled due to something known as 'vacuum polarisation'. During this phenomenon, photons break down to something known as ‘positrons’ and electrons for a split second. before combining together again. When they split, quantum mechanics creates a gravitational potential between the pair of ‘virtual’ particles. Dr Franson argues that the process might have a gradual impact on the speed of the photon, meaning that over 168,000 light years, the photons may have suffered a near five-hour delay. If the physicist is...

Been doing some construction work lately, and I've been told to keep an eye out for some of these types of things. Enjoy! LOL. I hope these pix can be seen.

Dark matter and normal matter have been wrenched apart by the tremendous collision of two large clusters of galaxies. The discovery, using NASA's Chandra X-ray Observatory and other telescopes, gives direct evidence for the existence of dark matter. "This is the most energetic cosmic event, besides the Big Bang, which we know about," said team member Maxim Markevitch of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. These observations provide the strongest evidence yet that most of the matter in the universe is dark. Despite considerable evidence for dark matter, some scientists have proposed alternative theories for gravity where it...