Spotless Sun: Blankest Year of the Space Age
Sept. 30, 2008: Astronomers who count sunspots have announced that 2008 is now the "blankest year" of the Space Age.
As of Sept. 27, 2008, the sun had been blank, i.e., had no visible sunspots, on 200 days of the year. To find a year with more blank suns, you have to go back to 1954, three years before the launch of Sputnik, when the sun was blank 241 times.
"Sunspot counts are at a 50-year low," says solar physicist David Hathaway of the NASA Marshall Space Flight Center. "We're experiencing a deep minimum of the solar cycle."
A spotless day looks like this:
A SOHO image of the sun taken Sept. 27, 2008.
The image, taken by the Solar and Heliospheric Observatory (SOHO) on Sept. 27, 2008, shows a solar disk completely unmarked by sunspots. For comparison, a SOHO image taken seven years earlier on Sept. 27, 2001, is peppered with colossal sunspots, all crackling with solar flares: image. The difference is the phase of the 11-year solar cycle. 2001 was a year of solar maximum, with lots of sunspots, solar flares and geomagnetic storms. 2008 is at the cycle's opposite extreme, solar minimum, a quiet time on the sun.
And it is a very quiet time. If solar activity continues as low as it has been, 2008 could rack up a whopping 290 spotless days by the end of December, making it a century-level year in terms of spotlessness.
Hathaway cautions that this development may sound more exciting than it actually is: "While the solar minimum of 2008 is shaping up to be the deepest of the Space Age, it is still unremarkable compared to the long and deep solar minima of the late 19th and early 20th centuries." Those earlier minima routinely racked up 200 to 300 spotless days per year.
Above: A histogram showing the blankest years of the last half-century. The vertical axis is a count of spotless days in each year. The bar for 2008, which was updated on Sept. 27th, is still growing.
Some solar physicists are welcoming the lull.
"This gives us a chance to study the sun without the complications of sunspots," says Dean Pesnell of the Goddard Space Flight Center. "Right now we have the best instrumentation in history looking at the sun. There is a whole fleet of spacecraft devoted to solar physics--SOHO, Hinode, ACE, STEREO and others. We're bound to learn new things during this long solar minimum."
As an example he offers helioseismology: "By monitoring the sun's vibrating surface, helioseismologists can probe the stellar interior in much the same way geologists use earthquakes to probe inside Earth. With sunspots out of the way, we gain a better view of the sun's subsurface winds and inner magnetic dynamo."
"There is also the matter of solar irradiance," adds Pesnell. "Researchers are now seeing the dimmest sun in their records. The change is small, just a fraction of a percent, but significant. Questions about effects on climate are natural if the sun continues to dim."
Pesnell is NASA's project scientist for the Solar Dynamics Observatory (SDO), a new spacecraft equipped to study both solar irradiance and helioseismic waves. Construction of SDO is complete, he says, and it has passed pre-launch vibration and thermal testing. "We are ready to launch! Solar minimum is a great time to go."
Coinciding with the string of blank suns is a 50-year record low in solar wind pressure, a recent discovery of the Ulysses spacecraft. (See the Science@NASA story Solar Wind Loses Pressure.) The pressure drop began years before the current minimum, so it is unclear how the two phenomena are connected, if at all. This is another mystery for SDO and the others.
Who knew the blank sun could be so interesting? More to come...
Author: Dr. Tony Phillips | Credit: Science@NASA
The Solar Wind Takes a Breather
I've always had a soft spot for an interplanetary pioneer called Ulysses. Built by the European Space Agency, it was launched in 1990 toward Jupiter, where the planet's powerful gravity yanked the craft out of the ecliptic plane and onto a looping path that carries it over and under the Sun every six years.
The Ulysses spacecraft, launched in 1990, recently completed its third and final pass over the Sun's polar regions.
European Space Agency
The initial mission concept, known as the International Solar Polar Mission, called for two identical craft - one European and one American - to study high-latitude regions of the Sun that can't be studied from Earth. But NASA reneged on its end of the deal, so Ulysses has soldiered on alone.
Recently it completed its third and final pass over the Sun's poles. That kind of longevity, far exceeding the planned 5-year-long mission, has really paid off. Ulysses's observations show that the solar wind is particularly feeble right now, with just 75% the strength it had a decade ago. In fact it's never been this weak since monitoring began a half century ago.
Space physicists had expected the flow to tail off, because the Sun's 11-year activity cycle is now at a minimum. But it's got far less punch than that seen during the last minimum. "The wind speed is almost the same, but the density and pressure are significantly lower," notes investigator David McComas (Southwest Research Institute), whose SWOOPS instrument aboard Ulysses has been key to the new finding.
The solar wind consists of plasma (ionized matter) and entrained solar magnetic field lines that pushed outward from the Sun's atmosphere into interplanetary space. Ulysses had previously shown that the wind comes off the Sun's poles faster and with less turbulence than it does from its midsection. But both the polar and equatorial flows have throttled back to historic lows.
There'd been earlier hints, in deep-space observations from IMP 8 and Voyager 2, that the solar wind variously ebbed and flowed during a solar cycle. Still, McComas and his colleagues, who detail their results in the September 18th issue of Geophysical Research Letters, don't know why the solar wind is taking a breather. One suspicion: perhaps the outflow is somehow being energized higher up in the Sun's corona, where there's less mass available to push outward into space.
Earth's magnetosphere (blue lines) protects our planet from space radiation and from the electromagnetic "wind" (at left) that continually flows from the Sun. During episodes of intense solar activity, as depicted here, the solar wind strengthens and can penetrate the magnetosphere more readily, triggering intense auroral displays.
NASA / Goddard Space Flight Center
In any case, the low flow means that the gigantic electromagnetic bubble that surrounds the Sun and planets must be shrinking inward and, with it, the solar system's boundary with interstellar space (called the heliopause). Both Voyager spacecraft are nearing this threshhold; they've aleady encountered a shock front inside the heliopause, and if this weak solar wind keeps up, Voyager 1 may find itself popping outside the heliosphere years sooner than expected.
Meanwhile, Ulysses itself is nearing the end of its historic mission. FLight controllers have been keeping a death watch all year, because the craft's source of heat and power (radioactive plutonium) has dwindled so much that the fuel lines are in imminent danger of freezing.
I contacted ESA project manager Richard Marsden for an update on the craft's health. "True to its name, Ulysses refuses to give up without a fight," he replied. "We're still getting science data, albeit only a few hours per day." The team has kept the fuel from freezing by firing thrusters every two hours. But the fuel is running low, and the team expects Ulysses to run dry sometime between the end of September and December. "With a bit of luck," Marsden adds, "we'll encounter the slow solar wind once again before then."
Hang in there, Ulysses!
Kelly Beatty, September 25, 2008, Sky&Telescope
Bio Fuels Come Under Fire
ROME (AFP) - Biofuels, once seen as a key factor in curbing greenhouse gas emissions, are behind the current global food crisis, major oil producers and consumers charged at an energy forum here on Monday.
"A conflict (is) emerging between foodstuffs and fuel ... with disastrous social conflicts and dubious environmental results," outgoing Italian Prime Minister Romano Prodi told the International Energy Forum here as rising food prices worldwide raise the spectre of famine in some countries.
"We have to examine very closely subsidy policies so as to avoid distortions in the allocation of resources," Prodi insisted.
Agricultural prices were not only being driven by rising demand but also by increased cultivation of biofuels, "creating strong tensions in a number of countries," he said.
Biofuels were developed as part of plans to limit and reduce greenhouse gas emissions, held responsible for global warming, but since they take up land that would otherwise be used for food production, they have been increasingly blamed for soaring food prices.
Qatari Energy Minister Abdullah bin Hamad al Attiyah said the world would have to choose "what its priority is going to be -- driving or eating."
He rejected suggestions that high oil prices were behind the food crisis.
"It's not oil that should be questioned, it's biofuels, which are at the root of the problem," al Attiyah said.
The food crisis was due to food shortages and not to high oil prices, he argued.
"Even the big rice exporters such as India, Bangladesh and Thailand are in the process of reducing their exports," he said. "
Venezuelan Energy Minister Rafael Ramirez said that biofuels were having a negligible impact on the oil markets.
"But look at the impact (they have) had on food prices. It's madness," he said, adding: "All the countries of Latin America have been hit by the surge in food prices."
Lawrence Eagles, chief analyst at the International Energy Agency (IEA) which represents the interests of the oil consuming countries, said he believed biofuels were "part of the equation" but it would be "wrong to focus solely" on just one element.
Rising food prices were due primarily to "very strong demand" for agricultural products in emerging countries, he said.
The IEA supported the use of second-generation biofuels, which used non-food plants as their base, Eagles argued.
"The second generation has its place in the palette of energy products," he said.
Meanwhile the head of Royal Dutch Shell, Jeroen van der Veer, said that too much importance was being attached to biofuels. Biofuels "will play a role" but were only one of a number of energy components in the mix, he said.
Copyright © 2007 Agence France Presse. All rights reserved. The information contained in the AFP News report may not be published, broadcast, rewritten or redistributed without the prior written authority of Agence France Presse.
Getting savvy about standby power
By Noah Buhayar, Fellow, Rocky Mountain Institute (www.rmi.org) | Posted Fri Nov 2, 2007 2:47pm PDT
Ever wonder how much electricity your household appliances use when they're supposedly off—in "standby" or "ready" mode? Think of the clock on your microwave, your DVD player that's on but not playing a movie, or the little sensor on the bottom of your TV that waits for a signal from your remote control.
It turns out that these "vampire" loads are gradually sucking away power—a lot of power.
An estimated 13 percent of household electricity use, according to a recent study published by the California Energy Commission, is from appliances in low-power mode (which is to say, not performing any of their primary functions).
Standby mode, the least amount of energy an appliance can use without powering down, is just one example. Many appliances have multiple low-power modes.
A DVD player, for instance, may have both a standby and sleep mode. Computers, as well, often save power by shutting down one or more components without turning completely off.
What it costs
The costs of these low-power modes are enormous. Standby power alone accounts for 5 of that 13 percent of household electricity use.
In 2000, a group of researchers from Lawrence Berkeley National Laboratory estimated that each year Americans spend about $4 billion just on standby power.
Generating that electricity puts roughly 27 million tons of CO2-equivalent emissions into the atmosphere (more than 3.7 million cars' worth) every year.
While the amount of low-power mode energy required by most new appliances is going down, the number of appliances (from washing machines to air conditioners) with continual power needs is increasing—eclipsing those savings. The U.S. Department of Energy estimates that standby power could consume as much as 20 percent of household electricity by 2010.
Worse yet, some of our electronics never go into low-power mode because they're hooked to networks that require constant feedback. Most desktop computers are left on all the time for just this reason—drawing (on average) a steady 70-watt current. The monitor may be off, but the processor, fan, and other hardware may still be running.
Your cable box, too, is perpetually drawing current as it talks to the network. Have an Internet phone? That, as well, is always on, ready to take a message.
Energy-efficiency experts are busy identifying ways that manufacturers can reduce the amount of energy required to maintain a network presence, hold a channel, or answer the phone when you're not there. Some promising work can be found here.
Why we don't sacrifice convenience?
If the net impact of all our leaky appliances is so huge, why aren't we compelled to change our habits—or do without a little convenience?
A colleague of mine here at Rocky Mountain Institute shares a useful anecdote. His home A/V system (TV, cable box, DVD player) and communications system (cable modem, WiFi router, Internet phone, and cordless phone with answering machine) uses about 45 watts of electricity continuously.
Even though he'd like to save that energy, he leaves the system on all the time. If he turns off the power bar that links everything to the wall, his phone won't take messages and he'll lose Internet connectivity.
What's the cost of this convenience? He estimates about $40 dollars a year.
What you can do
If you're looking to reduce your energy use and tread more lightly on the planet, changing your habits is a good starting point:
Shut your computer and printer down (all the way) when not in use. Some people find it useful to plug all their IT equipment into one power bar, then flip the switch once they've shut down.
If you have an A/V system that can be turned off entirely without sacrificing performance, do so.
Keep cell phone chargers out of the wall when you're not charging the phone. Those little power bricks often draw a little current—even when you're phone's not connected.
Making informed choices
Most importantly, educate yourself. The U.S. government's Energy Star program rates appliances and often has information about their standby (or low-power) mode energy use. For home electronics, low standby power use is a key criterion for qualifying products.
In 2006 alone, the program saved some $14 billion on Americans' utility bills and helped avoid more than 35,000 megawatts of peak power demand (equivalent to the capacity of 70 new power plants).
These small changes may not make a huge dent in your monthly electricity bill, but they can add up.
Noah Buhayar is a fellow at Rocky Mountain Institute