Archive for the ‘The Sun’ Category

Researchers at the Karolinska Institute, Sweden, say guidelines that advise people to stay out of the sun unless wearing sunscreen may be harmful, particularly in northern countries which have long, cold winters.

Exposure to ultraviolet radiation from sunlight is often cited as a cause of skin melanoma (malignant tumour of melanocytes) and avoiding overexposure to the sun to prevent all types of skin cancer is recommended by health authorities.

But the new study, which followed nearly 30000 women over 20 years, suggests that women who stay out of the sun are at increased risk of melanomas and are twice as likely to die from any cause, including cancer.

It is thought that a lack of vitamin D may be to blame. Vitamin D is created in the body through exposure to sunshine and a deficiency is known to increase the risk of diabetes, TB, multiple sclerosis and rickets.

Previous studies showed that vitamin D can increase survival rates for women with breast cancer while deficiencies can signal prostate cancer in men.

The study looked at 29518 Swedish women who were recruited from 1990 to 1992 and asked to monitor their sunbathing habits.

After 20 years there had been 2545 deaths and it was found that women who never sunbathed were twice as likely to have died from any cause.

Women who sunbathed in the mild Swedish summer were also 10% less likely to die from skin cancer, although those who sunbathed abroad in sunnier countries were twice as likely to die from melanoma.

Yinka Ebo, senior health information officer at Cancer Research UK, said striking a balance was important.

“The reasons behind higher death rates in women with lower sun exposure are unexplained . overexposure to UV radiation from the sun or sunbeds is the main cause of skin cancer.”

http://www.timeslive.co.za/thetimes/2014/05/09/avoiding-sunshine-could-kill-you-study-finds

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.

Solar Flare

The Earth will stay livable for another 1.75 to 3.25 billion years before ”a catastrophic and terminal extinction event for all life,” according to a new study.

After that, the planet will be in the Sun’s “hot zone” — meaning surface water would “evaporate.”

The study was published in the journal Astrobiology by astrobiologists at the University of East Anglia.

“We used stellar evolution models to estimate the end of a planet’s habitable lifetime by determining when it will no longer be in the habitable zone. We estimate that Earth will cease to be habitable somewhere between 1.75 and 3.25 billion years from now,” Andrew Rushby, from UEA’s school of Environmental Sciences and the leader of the research said on the UEA website. ”After this point, Earth will be in the ‘hot zone’ of the sun, with temperatures so high that the seas would evaporate. We would see a catastrophic and terminal extinction event for all life.

And life doesn’t necessarily mean humans — it can mean things as simple as micro-organisms.

“Of course conditions for humans and other complex life will become impossible much sooner — and this is being accelerated by anthropogenic climate change,” Rushby wrote. “Humans would be in trouble with even a small increase in temperature, and near the end only microbes in niche environments would be able to endure the heat.”

Rushby said that the most important part of figuring out the total habitable time for a planet is that it gives an idea of how long it takes for complex life to develop.

“Looking back a similar amount of time, we know that there was cellular life on earth. We had insects 400 million years ago, dinosaurs 300 million years ago and flowering plants 130 million years ago. Anatomically modern humans have only been around for the last 200,000 years — so you can see it takes a really long time for intelligent life to develop,” he wrote on his school site. “The amount of habitable time on a planet is very important because it tells us about the potential for the evolution of complex life — which is likely to require a longer period of habitable conditions.”

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Life on Earth will be obliterated by the heat of the sun (1.75 to 3.25 billion years from now)
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.The Earth will stay livable for another 1.75 to 3.25 billion years before ”a catastrophic and terminal extinction event for all life,” according to a new study.

After that, the planet will be in the Sun’s “hot zone” — meaning surface water would “evaporate.”

The study was published in the journal Astrobiology by astrobiologists at the University of East Anglia.

“We used stellar evolution models to estimate the end of a planet’s habitable lifetime by determining when it will no longer be in the habitable zone. We estimate that Earth will cease to be habitable somewhere between 1.75 and 3.25 billion years from now,” Andrew Rushby, from UEA’s school of Environmental Sciences and the leader of the research said on the UEA website. ”After this point, Earth will be in the ‘hot zone’ of the sun, with temperatures so high that the seas would evaporate. We would see a catastrophic and terminal extinction event for all life.

And life doesn’t necessarily mean humans — it can mean things as simple as micro-organisms.

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.“Of course conditions for humans and other complex life will become impossible much sooner — and this is being accelerated by anthropogenic climate change,” Rushby wrote. “Humans would be in trouble with even a small increase in temperature, and near the end only microbes in niche environments would be able to endure the heat.”

Rushby said that the most important part of figuring out the total habitable time for a planet is that it gives an idea of how long it takes for complex life to develop.

“Looking back a similar amount of time, we know that there was cellular life on earth. We had insects 400 million years ago, dinosaurs 300 million years ago and flowering plants 130 million years ago. Anatomically modern humans have only been around for the last 200,000 years — so you can see it takes a really long time for intelligent life to develop,” he wrote on his school site. “The amount of habitable time on a planet is very important because it tells us about the potential for the evolution of complex life — which is likely to require a longer period of habitable conditions.”

.This, in turn, can help us search for how complex life would develop on other planets. Scientists are looking for an Earth-size planet that’s in the habitable zone or the so-called “Goldilocks” zone — that sweet spot that’s not too hot and not too cold where water, which is essential for life as know it, could exist on the surface.

“Looking at habitability metrics is useful because it allows us to investigate the potential for other planets to host life, and understand the stage that life may be at elsewhere in the galaxy.”

The Earth is actually near the outer edge of the habitable zone. Scientists say that it would be much more likely for complex life to exist on planets that are closer to the sun than us than further from it, though the strip of “Goldilocks” space, in intrastellar terms, is quite small.

“Interestingly, not many other predictions based on the habitable zone alone were available, which is why we decided to work on a method for this. Other scientists have used complex models to make estimates for the Earth alone, but these are not suitable for applying to other planets,” Rushby wrote.

In April, NASA unveiled new planetary results from its Kepler mission, showing two very Earth-like planets.

“Two of the newly discovered planets orbit a star smaller and cooler than the sun. Kepler-62f is only 40% larger than Earth, making it the exoplanet closest to the size of our planet known in the habitable zone of another star,” NASA explains in a release. “Kepler-62f is likely to have a rocky composition. Kepler-62e orbits on the inner edge of the habitable zone and is roughly 60% larger than Earth.”

The distant duo are the best candidates for habitable planets that astronomers have found so far, said William Borucki, the chief scientist for NASA’s Kepler telescope. Both are Earth-sized and in the habitable zone.

Another key planet, Kepler 22b, was unveiled on December 5, 2011. It’s 2.4 times the size of the Earth, orbiting a Sun-like star every 290 days. Another, Gliese 581d, was discovered around the same time.

“One of the planets that we applied our model to is Kepler 22b, which has a habitable lifetime of 4.3 to 6.1 billion years. Even more surprising is Gliese 581d which has a massive habitable lifetime of between 42.4 to 54.7 billion years. This planet may be warm and pleasant for 10 times the entire time that our solar system has existed!” Rushby wrote.

The planets were discovered by NASA’s Kepler space telescope, which measures fluctuations in the brightness of more than 150,000 stars in order to detect planets. Scientists then used ground-based telescopes to peer at the information the spacecraft has gathered in order to analyze and verify its discoveries.

However, none of the discovered planets are perfect Earth analogues, Rusby wrote.

“To date, no true Earth analogue planet has been detected. But it is possible that there will be a habitable, Earth-like planet within 10 light-years, which is very close in astronomical terms. However reaching it would take hundreds of thousands of years with our current technology.”

He says that the best bet to transplant the human race remains right next door. On Mars.

“If we ever needed to move to another planet, Mars is probably our best bet. It’s very close and will remain in the habitable zone until the end of the Sun’s lifetime — six billion years from now.”

http://news.nationalpost.com/2013/09/19/life-on-earth-will-be-obliterated-by-the-heat-of-the-sun-1-75-to-3-25-billion-years-from-now/

SolarProminence_0

If you put a steamy cup of coffee in the refrigerator, it wouldn’t immediately turn cold. Likewise, if the sun simply “turned off” (which is actually physically impossible), the Earth would stay warm—at least compared with the space surrounding it—for a few million years. But we surface dwellers would feel the chill much sooner than that.

Within a week, the average global surface temperature would drop below 0°F. In a year, it would dip to –100°. The top layers of the oceans would freeze over, but in an apocalyptic irony, that ice would insulate the deep water below and prevent the oceans from freezing solid for hundreds of thousands of years. Millions of years after that, our planet would reach a stable –400°, the temperature at which the heat radiating from the planet’s core would equal the heat that the Earth radiates into space, explains David Stevenson, a professor of planetary science at the California Institute of Technology.

Although some microorganisms living in the Earth’s crust would survive, the majority of life would enjoy only a brief post-sun existence. Photosynthesis would halt immediately, and most plants would die in a few weeks. Large trees, however, could survive for several decades, thanks to slow metabolism and substantial sugar stores. With the food chain’s bottom tier knocked out, most animals would die off quickly, but scavengers picking over the dead remains could last until the cold killed them.

Humans could live in submarines in the deepest and warmest parts of the ocean, but a more attractive option might be nuclear- or geothermal-powered habitats. One good place to camp out: Iceland. The island nation already heats 87 percent of its homes using geothermal energy, and, says astronomy professor Eric Blackman of the University of Rochester, people could continue harnessing volcanic heat for hundreds of years.

Of course, the sun doesn’t merely heat the Earth; it also keeps the planet in orbit. If its mass suddenly disappeared (this is equally impossible, by the way), the planet would fly off, like a ball swung on a string and suddenly let go.

http://www.popsci.com/science/article/2013-07/if-sun-went-out-how-long-could-life-earth-survive?cmpid=obinsite

here-comes-the-sun

The universe will continue expanding and the objects which it is composed of will move apart faster, causing stars, such as the Sun, to become fainter, although in the case of the Sun this will not happen for “more than 5 billion years”, Nobel laureate in physics Brian Schmidt said.

The US-born astrophysicist, who lives in Australia, won the Nobel Prize in Physics in 2011 along with Adam Riess and Saul Perlmutter for discovering that the universe is accelerating.

The greatest challenge for scientists today is figuring out the “dark energy” of which nearly 70 percent of the universe is made, Schmidt said.

http://www.phenomenica.com/2013/04/sun-has-5-billion-years-left.html

 

An as yet undiscovered planet might be orbiting at the dark fringes of the solar system, according to new research.

Too far out to be easily spotted by telescopes, the potential unseen planet appears to be making its presence felt by disturbing the orbits of so-called Kuiper belt objects, said Rodney Gomes, an astronomer at the National Observatory of Brazil in Rio de Janeiro.

Kuiper belt objects are small icy bodies—including some dwarf planets—that lie beyond the orbit of Neptune.

Once considered the ninth planet in our system, the dwarf planet Pluto, for example, is one of the largest Kuiper belt objects, at about 1,400 miles (2,300 kilometers) wide. Dozens of the other objects are hundreds of miles across, and more are being discovered every year.

(See “Three New ‘Plutos’? Possible Dwarf Planets Found.”)

What’s intriguing, Gomes said, is that, according to his new calculations, about a half dozen Kuiper belt objects—including the remote body known as Sedna—are in strange orbits compared to where they should be, based on existing solar system models. (Related: “Pluto Neighbor Gets Downsized.”)

The objects’ unexpected orbits have a few possible explanations, said Gomes, who presented his findings Tuesday at a meeting of the American Astronomical Society in Timberline Lodge, Oregon.

“But I think the easiest one is a planetary-mass solar companion”—a planet that orbits very far out from the sun but that’s massive enough to be having gravitational effects on Kuiper belt objects.

Mystery Planet a Captured Rogue?

For the new work, Gomes analyzed the orbits of 92 Kuiper belt objects, then compared his results to computer models of how the bodies should be distributed, with and without an additional planet.

If there’s no distant world, Gomes concludes, the models don’t produce the highly elongated orbits we see for six of the objects.

How big exactly the planetary body might be isn’t clear, but there are a lot of possibilities, Gomes added.

Based on his calculations, Gomes thinks a Neptune-size world, about four times bigger than Earth, orbiting 140 billion miles (225 billion kilometers) away from the sun—about 1,500 times farther than Earth—would do the trick.

But so would a Mars-size object—roughly half Earth’s size—in a highly elongated orbit that would occasionally bring the body sweeping to within 5 billion miles (8 billion kilometers) of the sun.

Gomes speculates that the mystery object could be a rogue planet that was kicked out of its own star system and later captured by the sun’s gravity. (See “‘Nomad’ Planets More Common Than Thought, May Orbit Black Holes.”)

Or the putative planet could have formed closer to our sun, only to be cast outward by gravitational encounters with other planets.

However, actually finding such a world would be a challenge.

To begin with, the planet might be pretty dim. Also, Gomes’s simulations don’t give astronomers any clue as to where to point their telescopes—”it can be anywhere,” he said.

Other astronomers are intrigued but say they’ll want a lot more proof before they’re willing to agree that the solar system—again—has nine planets. (Also see “Record Nine-Planet Star System Discovered?”)

“Obviously, finding another planet in the solar system is a big deal,” said Rory Barnes, an astronomer at the University of Washington. But, he added, “I don’t think he really has any evidence that suggests it is out there.”

Instead, he added, Gomes “has laid out a way to determine how such a planet could sculpt parts of our solar system. So while, yes, the evidence doesn’t exist yet, I thought the bigger point was that he showed us that there are ways to find that evidence.”

Douglas Hamilton, an astronomer from the University of Maryland, agrees that the new findings are far from definitive.

“What he showed in his probability arguments is that it’s slightly more likely. He doesn’t have a smoking gun yet.”

And Hal Levison, an astronomer at the Southwest Research Institute in Boulder, Colorado, says he isn’t sure what to make of Gomes’s finding.

“It seems surprising to me that a [solar] companion as small as Neptune could have the effect he sees,” Levison said.

But “I know Rodney, and I’m sure he did the calculations right.”

http://news.nationalgeographic.com/news/2012/05/120511-new-planet-solar-system-kuiper-belt-space-science

Solar Flares in 2013…..

Posted: July 11, 2011 in The Sun

 

 

Last Tuesday, the Sun roared out a huge solar flare. NASA caught it on film, ranking it as a Class-M flare, just below the the most disruptive type of flare, Class-X.

NASA says it will give Earth a mere “glancing blow,” and the National Weather Service expects it will cause only minor disruptions to satellites and power grids.

For centuries, solar flares have been responsible for a multitude of earth-bound calamities, from blackouts to disrupted communications to strange lights in the sky. In 1859, the biggest flare on record hit, creating auroras worldwide and interrupting telegraph service for weeks.

http://science.nasa.gov/science-news/science-at-nasa/2008/06may_carringtonflare/

Just before dawn the day after the 1859 flare, skies all over erupted in red, green, and purple auroras so brilliant that newspapers could be read as easily as in daylight.  Stunning auroras pulsated even at near tropical latitudes over Cuba, the Bahamas, Jamaica, El Salvador, and Hawaii. 

 

Telegraph systems worldwide went haywire. Spark discharges shocked telegraph operators and set the telegraph paper on fire. Even when telegraphers disconnected the batteries powering the lines, aurora-induced electric currents in the wires still allowed messages to be transmitted.

The sun is now entering a particularly active time, says NASA, and big flares like the one fromlast Tuesday will likely be common during the next few years, with solar activity expected to peak around 2013. Most solar flares will only cause minor problems with satellites and power grids, but there’s always a chance that a monster like the one from 1859 could hit.

“The worst-case scenario is an extreme event,” says Michael Hesse, chief of NASA’s Space Weather Laboratory at the Goddard Space Flight Center in Maryland. “If it were to happen and we don’t take any precautions, it would probably knock out our power grid for an extended period of time and destroy a sizable fraction of our satellite infrastructure.”

http://www.pcmag.com/article2/0,2817,2386623,00.asp