At long last, here comes the sun (mission).
Never mind NASA’s numerous observatories; never mind the unmanned Pioneer 10 and Voyager probes careening toward the far reaches of the solar system—no craft has ever gone to the center of the solar system, the sun. This decade that will change. NASA is in the process of selecting the instruments for its Solar Probe Plus, a mission to launch by 2018 that will get closer to then sun than ever before, and hopefully find some answers to the open questions that remain about our life-giving star.
“The experiments selected for Solar Probe Plus are specifically designed to solve two key questions of solar physics: why is the Sun’s outer atmosphere so much hotter than the Sun’s visible surface, and what propels the solar wind that affects Earth and our Solar System,” said Dick Fisher, director of Nasa’s Heliophysics Division in Washington DC. [BBC News]
The probe isn’t quite setting the controls for the heart of the sun, Pink Floyd-style, but it will draw dangerously close.
The sun is breaking the known rules of physics—so said headlines that made the rounds of the Web this week.
That claim from a release out about a new study by researchers Jere Jenkins and Ephraim Fischbach of Purdue, and Peter Sturrock of Stanford. The work suggests that the rates of radioactive decay in isotopes—thought to be a constant, and used to date archaeological objects—could vary oh-so-slightly, and interaction with neutrinos from the sun could be the cause. Neutrinos are those neutral particles that pass through matter and rarely interact with it; trillions of neutrinos are thought to pass through your body every second.
In the release itself, the researchers say that it’s a wild idea: “‘It doesn’t make sense according to conventional ideas,’ Fischbach said. Jenkins whimsically added, ‘What we’re suggesting is that something that doesn’t really interact with anything is changing something that can’t be changed.’”
Could it possibly be true? I consulted with Gregory Sullivan, professor and associate chair of physics at the University of Maryland who formerly did some of his neutrino research at the Super-Kamiokande detector in Japan, and with physicist Eric Adelberger of the University of Washington.
When Ikaros unfurled, it unfurled like a spinning top blossoming into a pinwheel. Out in space earlier this month, the center piece of Japan’s solar sail was rotating quickly when it began to extend the arms that had been wrapped up inside. As they stretched out into a stiff X shape, like the stakes that hold a kite taut, the craft slowed to a gentler rotation (a consequence of conservation of angular momentum, like the way a figure skater’s spin slows down when she extends her arms). The JAXA scientists then could let Ikaros stretch the shining sail into a square that spanned 66 feet diagonally.
In Brooklyn this week, solar sail enthusiasts gathered for an international symposium. Last night Osamu Mori of the Ikaros team (seen above with a mock-up) was the toast of the party, and a group of experts joined him to celebrate and look forward to a bevy of new explorations. The roster included Planetary Society current director Louis Friedman and director-to-be Bill Nye, NASA’s Les Johnson, Malcolm McDowell of the University of Strathclyde in Scotland, and Roman Kezerashvili of the host New York City College of Technology.
“I feel like they deserve a ticker-tape parade here in New York City,” Friedman said, “rather than just showing up for a scientific conference.”
Ikaros hasn’t flown too close to the sun. It’s flown just close enough to ride the light.
Japan’s space agency JAXA confirmed on Friday that its solar sail project, Ikaros, achieved another of its goals: The sun’s photons pushed against the sail and accelerated the craft.
The effect stems from the cumulative push of light photons striking the solar sail. When measured together, it adds up to a small continuous thrust that does not require fuel use by the Ikaros craft. JAXA engineers used Doppler radar measurements of the Ikaros craft to determine that sunlight is pressing on the probe’s solar sail with a force of about 1.12 millinewtons (0.0002 pounds of force) [MSNBC].
Japan launched Ikaros in May and unfurled the sail in June. Now, JAXA scientists say, “with this confirmation, the IKAROS was proved to generate the biggest acceleration through photon during interplanetary flight in history.” Coming soon: A controlled flight in which the researchers turn the sail toward or away from the sun to control Ikaros’ velocity.
80beats: Today In Space: Japanese Craft Spreads a Solar Sail
80beats: Japan’s Venus-Bound Probe Will Hunt Volcanoes And Study Violent Storms
DISCOVER: Japan Stakes Its Claim in Space, on the Hayabusa mission
South Korea’s attempt to jump into the space race met with disaster today. A little more than two minutes after takeoff today, the nation’s Naro rocket exploded. It had been carrying a satellite, and South Korea was vying to become the tenth country to put a satellite in orbit with rockets assembled at home.
South Korea has invested more than 500 billion won (400 million dollars) and much national pride in the 140-ton Naro-1. The liquid-fuelled first stage of the rocket was made in Russia, while the second stage was built domestically, as was the satellite [AFP].
In Japan, meanwhile, happier news: Last month its space agency, JAXA, launched a batch of new missions into space that included its solar sail project, called Ikaros. Today it unfurled the sail, seen above in the blinding light of the sun.
After separating from Akatsuki [a separate probe going on to Venus], Ikaros began unfolding four panels that, when fully unfurled, should look like a square kite measuring 66 feet (20 meters) along its diagonal. Pictures sent back by a camera mounted on the spacecraft’s hub show the extension of four booms holding the panels, plus the unfurling of sail material. This is the “primary deployment” of the sail. During the secondary stage of deployment, the sail is stretched out to its full extent [MSNBC].
You can’t rise from the primordial ooze if that ooze is frozen. But about three billion years ago the sun was around thirty percent dimmer, meaning our planet should have been a snowball. The puzzle has haunted scientists for decades, but a study in Science has a new answer: It argues that a dense cloud of “fractal haze” enveloped the Earth.
This isn’t the first attempt to solve the early Earth conundrum. Carl Sagan, for one, had a few ideas. First, in 1972, he speculated that the atmosphere had ammonia which could trap heat, but later work showed that the sun’s ultraviolet radiation would have broken that ammonia down. In 1996 he tried again, saying that Earth might have had a thick haze, perhaps a nitrogen-methane mix, that blocked the ultraviolet but let in enough of the sun’s then-meager rays to warm the planet. Unfortunately, that too was a no go:
Early models assumed the haze particles were spheres, and that when individual particles collided, they globbed together to make bigger spheres. These spheres blocked visible light as well as ultraviolet light, and left the Earth’s surface even colder. “It basically led us to a dead end where we couldn’t have a warm early Earth,” said Eric Wolf, a graduate student in atmospheric sciences at the University of Colorado at Boulder and the first author of the new study. [Wired]
If I could offer you only one tip for the future, sunscreen would be it. The long-term benefits of sunscreen have been proved by scientists, whereas the rest of my advice has no basis more reliable than my own meandering experience.
But is even this sage advice subject to the “it’ll cause cancer, no wait, it’ll cure cancer” back-and-forth that plagues medical studies? Reading some headlines today, you might think so. Don’t toss out your tube of Banana Boat just yet, though.
The non-profit Environmental Working Group released another of its reports on the sunscreen industry, coming down hard on the chemicals it uses and the claims it makes in its advertising. Some stories about the report drew headlines like “Sunscreen May Hurt, Not Help;” “Your Sunscreen May Give You Cancer: Study;” and “Study: Many Sunscreens May Be Accelerating Cancer.”
EWG’s report claims that a Vitamin A compound called retinyl palmitate, used in some 40 percent of sunscreens, breaks down and causes skin damage under exposure to sunlight. The report cites research done under the Food and Drug Administration. But, according to dermatologist Henry W. Lim of Henry Ford Hospital:
These claims, says Lim, are based on a study in mice, which are far more susceptible to skin cancer than humans. “It’s dangerous to apply a finding in mice to humans, and I’ve spoken with a number of my colleagues about this and we all agree that it’s very premature to even cast doubt about the safety of this chemical.” The EWG also flagged products with oxybenzone, which it calls a “hormone-disrupting” compound. This, too, is based on mice data, says Lim; the animals were fed significantly greater amounts of the chemical than what’s commonly applied in sunscreen. Other research found no significant changes in blood hormone levels in human volunteers who were told to apply sunscreens containing oxybenzone every day for two weeks [U.S. News & World Report].
Its doom was sealed six years ago.
In 2004, UC Berkeley researchers say, this comet was tugged by Jupiter’s gravity into a path bound for destruction in the cauldron of the sun. And when its end finally came this March, astronomers captured the comet plunging deep into the sun on video (see below), watching it go farther into the light than any suicide comet seen before.
Seeing comets and other small objects approach the sun is difficult because the objects are overwhelmed by the sun’s brightness. Scientists were able to track this one closer to the sun than ever, before it it burned up in the sun’s lower atmosphere [Wired.com].
On this Earth Day, NASA’s focused on the sun. It just released the first images from the Solar Dynamics Observatory (SDO), launched in February to study our star in breathtaking detail at a rate of 60 images per minute. The new pictures include the evolution of this loop. Known as a prominence eruption, the loop was born from a relatively cold cloud of plasma, or charged gas, tenuously tethered to the sun’s surface by magnetic forces. Such clouds can erupt dramatically when they break free of the sun’s unstable hold [National Geographic].
Scroll through the gallery for a few more blazing wonders.
Astronomers keep turning up new exoplanets, and as the count rises, they keep edging closer to finding worlds like our own pale blue dot. Astronomer Jay Farihi thinks Earth-like worlds might be even more common in the universe than previously expected, based on evidence from rocky planets few astronomers are studying: The ones that don’t exist anymore.
Farihi’s research subjects are white dwarfs. In our galaxy, about 90 percent of stars will end their lives in this incredibly dense state once the star sheds its outer material and only the core remains. This is the fate of our sun. White dwarfs usually have atmospheres composed of the light elements helium and hydrogen, as the heavy elements have settled to the core. But about 20 percent of white dwarfs are different, showing heavy elements—what astronomers call “metals”—in their atmospheres. For decades, astronomers attributed this metallic pollution to the interstellar medium, the thin gas that permeates the space between stars. The idea was that white dwarfs were old stars that had been on several orbits around the Milky Way and had picked up bits of the interstellar medium as they went around [Space.com]. But Farihi thinks those elements are evidence of something else.