This is the warmest time of year in most of the U.S. And if we continue to pump heat-trapping greenhouse gases into the atmosphere, it’s going to get even warmer — not only in the summer, but throughout the year.
“How warm?” is the obvious question. So we've taken a look at how the number of extremely hot days are projected to increase in a variety of cities by 2050 and 2100 if emissions continue to grow unabated.
How many more extremely hot days will your city get?
The term “extremely hot” means different things in different places, of course. A reading of 100°F is rare in Madison, Wis., but on the other hand, in Phoenix 100°F days are not rare at all. These days, 115°F is considered an extremely hot day there. The mercury matches or tops that scorching number only about once a summer; but by 2100, more than 53 are projected. By contrast, a generally cooler city like Madison gets about 10 days at or above 90°F each year, so the temperature threshold there is lower. By 2100, Madison is expecting more than 67 days of 90°F-plus temps.
The graphic shows your city’s extremely hot threshold: the number of days that temperature is matched/topped on average during the period 1986-2005, and the number times that temperature is expected to be reached/topped by 2050 and by 2100. This assumes there’s no significant cutback in greenhouse-gas emissions.
Over the last few years we’ve been studying the orbits of dwarf galaxies and we expecting to find them buzzing at random around large galaxies. But looking out into the universe, we see some dwarfs undertaking an orderly dance with others, in coherent, well-defined orbits.
Such orbits are completely unexpected within our ideas of galaxy formation and evolution, so what do these new observations hold for cosmology?
The standard model of cosmology
While the cosmos appears to be a very strange place, recent years have seen significant advances in our scientific understanding of its inner workings.
Since the universe was born in the Big Bang, it has expanded and cooled, with gas pooling into stars and planets, guided by the dominating power of dark matter and dark energy.
The fact that the standard cosmological model, known as Lambda-CDM, works so well has left astronomers with a bit of a quandary, namely where do we look to learn more about the universe? Anomalies usually point the way to new scientific discoveries, but everything appears to fit perfectly. Well, not everything.
In recent years, a lot of cosmological focus has moved from the large-scale universe to our own backyard, into the surrounds of large galaxies such as our own Milky Way.
The problem with dwarfs
For more than a decade, astronomers have worried about the missing satellite problem. While we expect a galaxy like the Milky Way to be surrounded by hundreds and thousands of dwarfs, we see only a handful.
The Milky Way in a synthetic universe, surrounded by hundreds of randomly orbiting dwarf galaxies.
Image credit: NASA, ESA, and T. Brown and J. Tumlinson (STScI).
Some think that many of these dwarfs were destroyed by violent stellar explosions in the early universe, something that we are only now beginning to understand. Others wonder if the very nature of dark matter prevents these dwarfs from ever forming.
While the missing dwarfs are a head-scratcher, more peculiar dwarf problems are now confronting cosmology.
The coherent dance of dwarf orbits around the Andromeda Galaxy.
Credit: R. Ibata & Nature
The existence of such dancing of dwarfs is a serious challenge to our cosmological ideas, especially as our Milky Way is similarly strange, possessing its own Vast Polar Structure of dwarf galaxies.
Strangers in a strange land?
So, the dwarf populations of the Milky Way and its sister galaxy, Andromeda, are weird. Should this bother us? Maybe not.
Maybe our local patch is somehow strange, an outlier compared to the rest of the universe? If so, we shouldn’t worry as the vast majority of the galaxies would behave as expected.
But just how special is our local patch? We decided to take a look.
We wanted to find the locations and velocities of galaxies in the relatively nearby universe, and luckily for us, someone had already done the hard work in the Sloan Digital Sky Survey (SDSS).
Covering a huge swath of sky with a dedicated telescope, this data is available to all. For us, we used it to find big galaxies and their associated population of dwarf galaxies.
The cosmic two-step
With this data in hand, we could start to look at dwarf orbits. The test we applied was relatively simple, looking at dwarfs on opposite side of the larger galaxy and comparing velocities.
If galaxies were buzzing about at random, we would expect to see some chance alignments of dwarfs, but their orbital properties, their velocities, would also be random. In half the systems, both dwarfs would be orbiting in the same direction around the larger galaxy, whereas in the other half, the orbital directions oppose one another.
This is precisely what we found when we tried our test within the Millennium Simulation, one of our best synthetic representations of the universe.
But when we applied the test to our sample of galaxies from the SDSS, a rather peculiar signal emerged. Instead of seeing random dwarf orbits, we found that velocities tend to be correlated, with a pronounced signature pairs of dwarfs orbiting the larger galaxy in the same direction.
A schematic view of the correlated dwarf orbits about a larger galaxy.
Credit: Geraint Lewis and the Hubble Space Telescope Image Archive
Our new results indicate that, at least for the dwarf pairs we examined, well defined orbits occur in about half of the large galaxies we looked at, although as we are seeing only the brighter dwarfs, the signal could be stronger.
Our patch of the universe does not seem weird after all!
But what does it mean?
The ubiquity of well defined dwarf orbits pose a significant problem for our cosmological models. We know we have difficulties understanding the complexities of gas physics and star formation in the early universe, but it is a mystery how this could guide dwarf galaxies onto well defined orbits.
For others, these small-scale cosmological anomalies are pointing to a breakdown of the standard cosmological model where we may need to rethink the existence of dark matter or even the law of gravity.
At the moment, we just don’t know what these coherent orbits are telling us. But they are a significant chink in the cosmological armour, and may be the anomalies that are pointing towards new universal physics.
Animals have evolved to occupy almost all corners of the Earth. To survive, no matter the weather outside, they all need temperature-sensitive bodily reactions to work. This is easy for warm-blooded animals, such as humans, because they have the ability to maintain their body temperature.
But cold-blooded animals can’t do that. When the weather changes and the mercury swings one way, their cells get exposed to that change in temperature. Yet cold blooded animals survive just fine. Michael Welte, associate professor of biology at the University of Rochester, may have just discovered how. His team’s findings have been published in the Journal of Cell Biology.
At the molecular level, the key to survival is to ensure that proteins are being made at the right time and in the right amount. To do that every cell in the body has an assembly line. This is partly driven by motor proteins, which act like cargo trains delivering the messenger molecule RNA that comes from DNA located in the cell’s nucleus. RNA needs to reach the end of the assembly line where special organelles, called ribosomes, decode the message and make the protein.
“We have found a molecule that keeps protein production balanced when temperatures change,” said Welte. “It happens to do so by controlling cellular transport.”
Theirs was a serendipitous discovery. They were studying fruit flies, which happen to be cold blooded, when they found that making some proteins is difficult for the flies when temperatures change.
As temperatures fall, the protein assembly line slows down more than the cargo trains. This creates an imbalance where, when the motor proteins reach the ribosomes, if the messenger RNA molecules are not used up immediately, they could be lost forever. This could throw the cell completely off-balance, stopping protein synthesis altogether.
But Welte found a special protein, called Klar, that keeps the balance intact. Klar behaves like the emergency brakes of the cargo trains. As soon as the mercury level falls, Klar slows down the motor proteins carrying messenger RNA molecules. Now that the pace of delivery of the blueprints matches the rate of making proteins, the assembly line stays balanced.
In fruit flies, Welte found that the protein assembly line balance is especially important for making a protein called Oskar. Egg cells, from which a fruit fly will hatch, produce Oskar. In the egg cell that still has not decided its orientation, Oskar accumulates and defines where the posterior end will be. The posterior end of the cell will later give rise to the tail after hatching. If Oskar is not made properly that the eggs will not be able to hatch.
When Welte used genetic tools in fruit flies to remove Klar from the cell, he found that losing Klar had no effects on the baby flies that hatched at normal temperature. But as soon as the temperature was lowered, the eggs could not hatch. Development of the fruit fly is completed at colder temperatures only when Klar is present in the egg cell.
Klar is found in all insects in the animal kingdom, where Welte thinks that Klar might be playing a similar role. It would also be interesting to find a similar protein in other cold-blooded animals.
Body temperature in humans does not fluctuate as much as it does in flies. But, with fevers and other conditions, our cells could be exposed to fluctuations in temperature as well. Welte speculates that a similar mechanism could be taking place in our cells as well, keeping our protein production stable. “While we don’t have the Klar protein in our cells, the mechanism for producing proteins is very similar,” Welte said.
Anwesha Ghosh does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.
A campaign to promote male circumcision to prevent AIDS infection also indirectly benefits women by reducing their risk of contracting the HIV virus, according to a study presented at the world AIDS forum Friday.
In a South African community where large numbers of men had been circumcised, women who only had sex with circumcised partners had a 15-percent-lower risk of being infected by HIV compared with women who also had uncircumcised partners, it found.
"The risk reduction is small, but it is a start," said investigator Kevin Jean of France's National Agency for AIDS Research (ANRS).
The study was presented on the final day of the 20th International AIDS conference in Melbourne.
The World Health Organisation (WHO) recommends voluntary circumcision as an option for men in 14 sub-Saharan countries struggling with high rates of human immunodeficiency virus (HIV).
The guidelines -- which have triggered a multimillion-dollar programme -- are founded on evidence from three trials carried out in South Africa, Kenya and Uganda.
These concluded that circumcision resulted in a reduced HIV risk -- for men -- of between 50 and 60 percent.
What has been fiercely debated, though, is the impact of male circumcision on women.
Key questions included whether, if large numbers of men were circumcised, the infection risk for women would fall too.
Another issue raised was that circumcised men might think wrongly that they were fully shielded from HIV and ignore advice to wear a condom -- thus increasing the risk for women.
Looking at these questions, the new study enrolled 2,452 women aged between 15 and 29 who lived in Orange Farm in South Africa, where the first of the landmark trials was carried out in 2002.
The women's blood was tested in 2007, 2010 and 2012, and they were also asked questions about their sexual behaviour, as was a representative sample of local men.
During this time, the prevalence of circumcision among men in the community rose from 12 percent to 53 percent.
Over 30 percent of women reported having sexual relations only with circumcised men: 17.8 percent became infected during the study period.
But among women who had sex with uncircumcised men, the prevalence of HIV was almost twice as high, at 30.4 percent.
- Indirect benefit -
In an interview with AFP, Jean said women who had only circumcised partners were relatively a small group.
Statistically speaking, they were less likely to have multiple sex partners, a well-known boost of infection risk.
This explained in part why the risk reduction -- 15 percent, averaged out over the whole period -- seems relatively small, Jean said.
Further work will show whether this protection improves over time as more men in the community become circumcised and uninfected younger men have the operation, he said.
There was also good news from the questions on sex behaviour: men were unlikely to engage in unprotected intercourse after being circumcised, he said.
"What we are seeing is an indirect effect," he said. "Circumcision reduces HIV among men, and if fewer men are infected, they are less likely to infect women."
He stressed, though: "The message still has to be made that they use condoms."
An earlier presentation at the Melbourne conference found that offering men compensation in the form of food vouchers worth around $9 or $15 (6.5 euros or 11 euros) was a useful incentive for circumcision.
Most countries in the voluntary circumcision campaign remain far short of reaching their target numbers.
Investigators have found that many men are deterred by the loss of wages from time off work to have the operation, and the cost of travelling to and from the clinic to have it carried out.
The protective effect from circumcision appears to lie in removal of cells in the foreskin which are especially vulnerable to penetration by HIV.
Cotswold Archaeology and local divers hope to solve mystery of how the warship London sank off the Southend coast
A major underwater rescue excavation is being mounted this summer by English Heritage to solve a 349-year-old mystery: how warship the London managed to blow itself up without firing a shot at the enemy, in broad daylight, within sight of the Southend seafront.
Cotswold Archaeology and local divers hope to recover as much information as possible before the ship's splinted timbers finally disintegrate. Much of the wreck has been preserved in pristine condition on the bed of the Thames Estuary, sealed within a deep layer of silt and mud, but it has been on the national inventory of heritage at risk since it was realised that timbers were being scoured bare and quickly destroyed by changing tidal patterns, including the dredging for the huge new London Gateway port development.
In 1665 the explosion was a humiliating disaster. The London was blown in half, and sank almost instantly. At least 300 people died, perhaps many more: a surprising number of the human remains recovered so far have proved to be female, suggesting that as well as the 350 crew, plus extra gunners for the newly mounted artillery, the 17th century ship was carrying many of their wives and sweethearts.
"It's a good question why there were so many women, and one on which I wouldn't care to speculate," archaeologist and diver Dan Pascoe said.
Only 24 men and one woman survived the disaster, clinging to the ornately carved stern which the archaeologists believe was left sticking vertically out of the shallow water.
A few hours later the London's new commander, Sir John Lawson, would have gone down with the ship: as it was, several of his children and other members of his family died. The London had been refitted at Chatham, and was sailing to Gravesend to collect him and become his flagship in the second Anglo-Dutch wars. The ship was carrying 300 barrels of gunpowder and it is believed that a 21 gun salute was being prepared. "Clearly there was some hiccup," Mark Dunkley, maritime archaeologist at English Heritage said.
Apart from the mystery of its end, the wreck is of great historic importance. The London was one of only three completed wooden Second Rate ships, with elaborate carved decoration that made them as much status symbols as weapons of war, built for the English Fleet between 1642 and 1660. It is the only one that survives.
Archaeologists love sudden catastrophes. Most ships in history have become worn out and been stripped and broken up. A ship that sinks like the London, or the Mary Rose a century earlier, goes to the bottom with all their evidence of daily life: the cooking pots, beer tankards, candle sticks, cap badges, food barrels, rats and cats.
Diving conditions on the London are atrocious. They have an hour to work between tides, visibility is often down to inches, and the wreck lies so close to the shipping lane that they are buffeted by every passing vessel.
Working mainly by touch and the faint glimmer of their head torches, the divers are helping map the wreck and bring up finds every day: the most recent haul includes a pistol and musket shot, part of a weighing scales and spoons. The clay pipe and the tallow candles they also found "look very much like a smoking gun", archaeologist Steve Webster observed.
The finds are all being recorded and packed on the end of Southend pier as they come ashore, watched by curious sun bathers, strollers and local volunteers working with Southend Museum, where many will go on display.
Scores of the ship's guns must also still lie buried in the silt. Some were retrieved immediately after the wreck. The Royal Armouries at Fort Nelson has a fine French naval gun recovered in the 1960s, which must have been a captured prize, and is also displaying two bronze guns allegedly illegally removed from the wreck more recently. One of these was made in the 1590s by Peter Gill, a royal gun founder, and one bears the Commonwealth arms – together showing the variety of artillery in service on one of Charles II's ships.
Steven Ellis, a fishmonger from Leigh-on-Sea, hobby diver and passionate amateur historian, has been watching over the wreck for years. Local fishermen phone him if they spot anybody dubious near the wreck – one recent intruder proved to be a survey boat from Cotswold Archaeology.
He dives most days, and hopes to be back when work resumes next summer. Among the objects he has recovered are two human skulls: "Sometimes when I get home, I just sit down in the kitchen and I can't get the thought of all those people, all those lives lost, out of my mind," he said.
Death marks new and alarming cross-border development in world's biggest epidemic spreading across three countries
A man has died of ebola in Lagos, the first confirmed case of the highly contagious and deadly virus in Africa's most populous metropolis.
Patrick Sawyer, a 40-year-old Liberian civil servant, collapsed on arrival in Nigeria's main airport on Sunday, health officials said. His condition rapidly deteriorated before he died, said Abdulsalami Nasidi, project director at the Nigeria Centre for Disease Control, who attributed his death to ebola.
Officials at the World Health Organisation confirmed a sample from Nigeria was being tested for ebola, but did not confirm the results.
The death marks a new and alarming cross-border development in a disease that has spiralled into the world's biggest epidemic, spread across three west African countries. At least 660 people have died in Guinea, Liberia and Sierra Leone since ebola was first diagnosed in February.
The pathogen is passed through contact with bodily fluids of infected patients, and has no known cure, although chances of survival improve dramatically with early detection and treatment.
But weak health systems and frequent cross-border travel have hampered efforts to contain the virus in a region which has never before experienced an outbreak.
Lagos state authorities said they had requested the flight's manifest to contact the other passengers, and began distributing protective clothing to health workers, state health advisor Yewande Adeshina said. Sawyer flew from Liberia's capital of Monrovia, with a brief flight stopover in nearby Togo. His sister is believed to have died of ebola in the last month, a Liberian official told the Guardian.
Rumours about the virus – which causes a painful fever that degenerates into internal and external bleeding – were met with scepticism from residents in the crowded business district where Sawyer was treated. "I cannot believe it is true," said trader Segun Kosoko, who said he had seen two traders donning face masks.
Experts have also been alarmed by the disease's wide geographical spread, from Guinea's remote interior forest region, where it originated, to densely populated coastal regions.
Ghana has had several unconfirmed scares, while Sierra Leone's capital Freetown recorded its first confirmed case this week. Authorities there were forced to launch a public appeal after the victim slipped out of hospital. Her family forcibly removed her – as many have done, either fearing they would catch the disease while in quarantine, or doubting its existence.
Radio stations in Freetown, a city of about 1 million people, broadcast the appeal to locate the woman, named as Saudatu Koroma. "She is a positive case and her being out there is a risk to all. We need the public to help us locate her," the appeal stated.
Koroma, 32, had been admitted to an isolation ward while blood samples were tested for the virus, said Sidi Yahya Tunis, a health ministry spokesman.
Meanwhile in Liberia this week, a man burned down a room in the ministry of health after his 14-year-old relative died of ebola. He said a lack of doctors and nurses – many of whom have been ostracised from their communities – had led to the boy's death.
Nigeria's ministry of health urged residents to follow guidelines to prevent the virus' spread, and launched a hotline number.
Back in 2012, the Sun erupted with a powerful solar storm that just missed the Earth but was big enough to "knock modern civilization back to the 18th century," NASA said.
The extreme space weather that tore through Earth's orbit on July 23, 2012, was the most powerful in 150 years, according to a statement posted on the US space agency website Wednesday.
However, few Earthlings had any idea what was going on.
"If the eruption had occurred only one week earlier, Earth would have been in the line of fire," said Daniel Baker, professor of atmospheric and space physics at the University of Colorado.
Instead the storm cloud hit the STEREO-A spacecraft, a solar observatory that is "almost ideally equipped to measure the parameters of such an event," NASA said.
Scientists have analyzed the treasure trove of data it collected and concluded that it would have been comparable to the largest known space storm in 1859, known as the Carrington event.
It also would have been twice as bad as the 1989 solar storm that knocked out power across Quebec, scientists said.
"I have come away from our recent studies more convinced than ever that Earth and its inhabitants were incredibly fortunate that the 2012 eruption happened when it did," said Baker.
The National Academy of Sciences has said the economic impact of a storm like the one in 1859 could cost the modern economy more than two trillion dollars and cause damage that might take years to repair.
Experts say solar storms can cause widespread power blackouts, disabling everything from radio to GPS communications to water supplies -- most of which rely on electric pumps.
They begin with an explosion on the Sun's surface, known as a solar flare, sending X-rays and extreme UV radiation toward Earth at light speed.
Hours later, energetic particles follow and these electrons and protons can electrify satellites and damage their electronics.
Next are the coronal mass ejections, billion-ton clouds of magnetized plasma that take a day or more to cross the Sun-Earth divide.
These are often deflected by Earth's magnetic shield, but a direct hit could be devastating.
There is a 12 percent chance of a super solar storm the size of the Carrington event hitting Earth in the next 10 years, according to physicist Pete Riley, who published a paper in the journal Space Weather earlier this year on the topic.
His research was based on an analysis of solar storm records going back 50 years.
"Initially, I was quite surprised that the odds were so high, but the statistics appear to be correct," said Riley.
CAPE CANAVERAL Fla (Reuters) - For the past four months, a team of researchers have been living in a mockup Mars habitat on a Hawaiian volcano practicing isolated living on the Red Planet.
For the most part, expedition leader Casey Stedman and his five crewmates have stayed inside their 1,000-square foot (93-square meter) solar-powered dome, venturing out only for simulated spacewalks and doing so only when fully attired in mock spacesuits.
"I haven’t seen a tree, smelled the rain, heard a bird, or felt wind on my skin in four months,” Stedman wrote in a blog on Instagram. Stedman is a U.S. Air Force Reserve officer, graduate student at Embry-Riddle Aeronautical University Worldwide.
“We are simulating a long-duration mission on Mars, with a focus on crew psychology in isolation,” the crew said during an online interview with Reddit on Sunday.
Crewmembers, who include a NASA chemical engineer and a neuropsychologist at the Fort Wayne Neurological Center in Indiana, have been isolated from direct human contact and have been eating dehydrated and shelf-stabilized foods.
“We’ve basically been subsisting on mush. Flavorful mush, but mush nonetheless,” crewmember Ross Lockwood wrote on Instagram. Lockwood is finishing a doctorate in physics at the University of Alberta.
The habitat, which is outfitted with waterless composting toilets, is basically self-sustaining except for a water resupply and wastewater recovery every two- to three weeks.
Communications with the outside world have been time-delayed to match the 20-minute travel time of radio waves passing between Earth and Mars. In addition to a battery of daily psychological surveys, the researchers tend to science projects and other studies, including expeditions outside the habitat to scout Mars-like features on Hawaii's Mauna Loa volcano. The landscape is similar to a region on Mars known as Tharsis. For fun, there are movies, board games and exercise, Lockwood told Reddit.
“We don't have a lot of spare time, but I count work as part of the fun as well. Planning EVAs (spacewalks), preparing food, even chores - these are all enjoyable activities,” he said.
The operational part of the Hawaii Space Exploration Analog and Simulation mission, known as Hi-SEAS 2, wraps up on Friday, but it will take months to synthesize all the findings.
The point of the project is to create guidelines for future missions to Mars, the long-term goal of the U.S. human space program.
“Hopefully, when we send humans to Mars, we will have done enough missions like HI-SEAS that we'll remember to bring the really important stuff, like extra toilet paper,” mission support team member Gary Strawn said on Reddit.
The simulation, which is funded by NASA and overseen by the University of Hawaii, began on March 28.
The discovery of the fossilised remains of a creature that looks a little like a giant beak-less chicken has led scientists to a striking hypothesis: at one time all dinosaurs had feathers.
Researchers were aware that early flesh-eating dinosaurs had feathers, but the finding of the metre-long herbivore on a Siberian river bank has led experts to conclude that all dinosaurs from the Triassic period – more than 200m years ago – were feathered.
As dinosaurs evolved and in some cases developed armour, they lost the feathers, which were probably used for insulation and communication rather than flight.
"This little chap from Siberia has feathers without a doubt. The conclusion we are tentatively putting forward is that feathers were present in all dinosaurs."
Benton said the feathers kept dinosaurs warm, meaning that unlike cold-blooded lizards, they were able to operate in colder temperatures and at night. As dinosaurs grew bigger, feathers would have hindered them by making them too warm and compromised their defensive armour.
The fresh evidence that vegetarian dinosaurs were also cloaked in feathers was found at a site called Kulinda on the banks of the Olov river in Siberia. They found fossil remains showing it had scales on its tail and shins and short bristles on its head and back. But the thrilling discovery was feathers preserved as carbon-rich films on the rock.
These were well-preserved apparently because the animal's carcass had not been picked over by scavengers but were probably washed away by a river and then encased in mud.
The new dinosaur has been named Kulindadromeus zabaikalicus. It was a plant-eater with long hind legs and short arms and five strong fingers. Six skulls and several hundred partial skeletons were found at Kulinda.
The findings are published in a paper in the journal Science. Pascal Godefroit, the lead author, from the Royal Belgian Institute of Natural History in Brussels, said he was amazed when he realised the new dinosaur's limbs had been covered in feathers. "Our new find clinches it: all dinosaurs had feathers, or at least the potential to sprout feathers."
More than 90% of human DNA is doing nothing very useful, and large stretches may be no more than biological baggage that has built up over years of evolution, Oxford researchers claim.
The scientists arrived at the figure after comparing the human genome with the genetic makeup of other mammals, ranging from dogs and mice to rhinos and horses.
The researchers looked for sections of DNA that humans shared with the other animals, which split from our lineage at different points in history. When DNA is shared and conserved across species, it suggests that it does something valuable.
Gerton Lunter, a senior scientist on the team, said that based on the comparisons, 8.2% of human DNA was "functional", meaning that it played an important enough role to be conserved by evolution.
"Scientifically speaking, we have no evidence that 92% of our genome is contributing to our biology at all," Lunter told the Guardian.
Researchers have known for some time that only 1% of human DNA is held in genes that are used to make crucial proteins to keep cells – and bodies – alive and healthy. The latest study, reported in the journal Plos Genetics, suggests that a further 7% of human DNA is equally vital, regulating where, when, and how genes are expressed.
But if much of our DNA is so worthless, why do we still carry it around? "It's not true that nature is parsimonious in terms of needing a small genome. Wheat has a much larger genome than we do," Lunter said. "We haven't been designed. We've evolved and that's a messy process. This other DNA really is just filler. It's not garbage. It might come in useful one day. But it's not a burden."
Some of our DNA is left over from ancient viruses that inserted their genetic material into our DNA – or our ancestors DNA – and got mutated to pieces over millennia of evolution. Some still have the ability to jump around in our genomes, adding to the filler as they do so, but are so crippled they cannot break out.
Though 8.2% seems a small portion of DNA to call functional, the meaning of the word is very specific. In the Oxford study, DNA is "functional" if it affects our reproductive fitness.
But other scientists take a broader view of what it means for DNA to be functional. Most of the 92% that Lunter's group says is not functional DNA is still active in some way in the body.
"Many [DNA] elements that play important roles in human disease are not evolutionarily conserved. Some of these have human-specific functions, some are involved in late-onset diseases like Alzheimer's, and others are simply missed by current comparative genomics methods," said Manolis Kellis, a computational biologist at MIT who was not involved in the study. "We cannot simply ignore the remaining 90% of the genome that is not evolutionarily conserved."
"Evolution can tell you whether something is important or not important, but it doesn't tell you what that something actually does," he added.
(Reuters) - Scientists will begin excavation early next week of an ancient Wyoming sinkhole containing a rare bounty of fossil remains of prehistoric animals, such as mammoths and dire wolves, preserved in unusually good condition, researchers said on Thursday.
The two-week dig, set to begin next Monday under the direction of Des Moines University paleontologist Julie Meachen, marks the first exploration of Natural Trap Cave in north-central Wyoming since its initial discovery in the 1970s.
At that time, scientists found that the 85-foot-deep cavern formed a natural repository for a rich fossil record that may date back as far as 100,000 years, but a full-scale expedition into the sinkhole has not previously been attempted.
The cave, formed by the collapse of limestone bedrock at the base of the Bighorn Mountains, became a tomb for thousands of ancient mammals that stumbled into the 15-foot-wide mouth of the sinkhole, then concealed by vegetation, and plunged to their deaths.
Conditions in the underground chasm, which widens to 120 feet at its base, are cold and damp, offering a degree of preservation for fossils generally associated only with those found frozen in ice in Siberia and the Arctic, Meachen said.
"They fell into a refrigerator," she said of animals such as camels, American lions, cheetahs, woolly mammoths and short-faced bears.
Meachen will lead a team of international scientists as they rappel from the outer rim of the cave's opening – covered for decades by a metal grate installed by federal land managers – to the depths below, where they will load fossils into buckets to be hoisted to the surface.
Analysis of recovered fossils is expected to provide new insights into the climate, diets and genetic diversity of North American mammals that disappeared during the Ice Age extinction of more than 10,000 years ago.
Meachen said there may also be an opportunity to draw inferences tied to an emerging theory that the mass extinction was linked more to overhunting by humans, whose appearance in North America coincided with a die-off long thought to be influenced mostly by climate.
Meachen said she had trained at a rock-climbing gym for the descent and the more arduous ascent, also by rope, but remained leery of entries and exits from the cave.
Earthlings often wonder if life exists on other planets, and researchers said Wednesday that hunting for traces of pollution from distant worlds could provide the answer.
Under certain conditions, astronomers in the next decade might be able to detect the presence of an industrialized alien society, according to a study by the Harvard-Smithsonian Center for Astrophysics.
Already, astronomers can study the atmospheres of planets outside our solar system for the presence of oxygen and methane, which could be produced by intelligent life or by microbes.
But an extraterrestrial civilization might also spew chlorofluorocarbons (CFCs) into the atmosphere, much the same way we do on Earth, said the study.
CFCs are chemicals used in solvents and aerosols that destroy the ozone layer.
Astronomers may be able to detect evidence of these CFCs on faraway planets using the James Webb Space Telescope, an $8.7 billion project that NASA is scheduled to launch in 2018.
The JWST will be between 10 and 100 times more powerful than NASA's Hubble Space Telescope, according to the US space agency.
However, there are limits to what kinds of pollution the JWST might find, and under which conditions, the Harvard astronomers said.
For instance, atmospheric levels of CFCs would have to be 10 times those on Earth for the JWST to be able to detect them.
Also, the JWST would only be able to hunt for this pollution on Earth-like planets that are circling white dwarfs, which are once-potent stars that have died and lost all their hydrogen fuel.
An even stronger instrument, which has not been invented yet, would be necessary to find pollution on a planet like Earth that is orbiting a bright star like our sun, said the report in The Astrophysical Journal.
The study authors raised the possibility that while this method aims to detect intelligent life, it might lead not to actual life, but instead to a civilization that has annihilated itself.
Some pollutants can persist in Earth's atmosphere for 50,000 years, while others last just 10 years -- and the absence of the latter might suggest that living sources are gone.
"We could speculate that the aliens wised up and cleaned up their act," said co-author Avi Loeb.
"Or in a darker scenario, it would serve as a warning sign of the dangers of not being good stewards of our own planet."
