Using the traditional fuel-burning rockets that carried humans on lunar missions, it would take a manned spacecraft six months to travel from the Earth to Mars. While you could find volunteers in spades willing to trade a year in a tin can for a glimpse of another planet, osteoporosis-inducing weightlessness and dangerous radiation render a lengthy trip unfeasible. But attention has turned to ion engines. While a combustion rocket thrusts a space shuttle through the atmosphere, then lets it coast to its destination, ion engines are able to effect a more continuous thrust:

Ion engines, on the other hand, accelerate electrically charged atoms, or ions, through an electric field, thereby pushing the spacecraft in the opposite direction. They provide much less thrust at a given moment than do chemical rockets, which means they can't break free of the Earth's gravity on their own.

But once in space, they can give a continuous push for years, like a steady breeze at the back of a sailboat, accelerating gradually until they're moving faster than chemical rockets.

Engineers at the Ad Astra are seeing promise in VASIMR, an ion engine that uses a radio frequency generator to heat charged particles and create greater thrust than other similar engines. Ad Astra plans to attach a solar-powered VASIMR engine to the International Space Station for tests, and, if they are successful, could use VASIMR periodically to thrust the ISS back into the Earth's orbit.

But, if the engine were powered by an onboard nuclear reactor, its applications could be much more profound. Using 1000 times the energy of a solar-powered VASIMR, a nuclear-powered VASIMR engine could propel a manned spacecraft to Mars in a mere 39 days. Although the technology to play a nuclear reactor on a space shuttle is still a ways off, many in astrophysics feel the project holds enormous promise. NASA has provided Ad Astra with a small stipend for VASIMR development, and NASA chief Charles Bolden had high praise for the possibility of shortened space travel:

If engines, such as VASIMR, could be developed to take people to the Red Planet in 40 days, "that puts it inside the range of what we feel comfortable of doing with humans," he told New Scientist. "Something like VASIMR – that's a game changer."

Ion engine could one day power 39-day trips to Mars [New Scientist via Futurismic]

Sun spots are a form of solar weather that goes through 11 year cycles. They are also associated with massive ejections of plasma and electromagnetic particles from the sun, which can interfere with earth weather and effect communications systems as well as the electrical grid. Understanding how sunspots work is a key to protecting earth from these plasma bursts.

According to the National Science Foundation:

Ever since outward flows from the center of sunspots were discovered 100 years ago, scientists have worked to explain the complex structure of sunspots, whose number peaks and wanes during the 11-year solar cycle. Sunspots accompany intense magnetic activity that is associated with solar flares and massive ejections of plasma that can buffet Earth's atmosphere. The resulting damage to power grids, satellites and other sensitive technological systems takes an economic toll on a rising number of industries.

Creating such detailed simulations would not have been possible even as recently as a few years ago, before the latest generation of supercomputers and a growing array of instruments to observe the sun. The new computer models capture pairs of sunspots with opposite polarity. In striking detail, they reveal the dark central region, or umbra, with brighter umbral dots, as well as webs of elongated narrow filaments with flows of mass streaming away from the spots in the outer penumbral regions. They also capture the convective flow and movement of energy that underlie the sunspots, and which are not directly detectable by instruments.

The models suggest that the magnetic fields within sunspots need to be inclined in certain directions in order to create such complex structures. The authors conclude that there is a unified physical explanation for the structure of sunspots in umbra and penumbra that's the consequence of convection in a magnetic field with varying properties.

via NSF

Image by Matthias Rempel, NCAR

A team of astrophysicists led by Mark Krumholz at University of California Santa Cruz have been using computers to model the behavior of proto-supermassive stars. In this video, you can see what happens when a ball of firey gas starts to turn into a supermassive star. First, the star explodes as it's forming. The explosion throws out balls of gas that turn into a star system of several massive stars orbiting the original proto-star. On the left, you can see the star system from above; on the right, you see a cutaway view from the side.

Eventually, this model predicts, the original star will eat the other stars in the system with it. And the result could be a star far more massive than the one our planet revolves around. The best part of this study is that it's basically the astrophysics equivalent of a Michael Bay movie: It's all about the behavior of REALLY GIANT explosions. In space!

What Krumholz and his team have proven here is that stars can grow larger by accretion - accumulating more matter - even after they've ignited into a ball of continuous nuclear explosions. Until recently, it was believed that stars emitted so much energy that they couldn't continue to absorb gas and other matter after they had ignited.

SOURCES:

The Formation of Massive Star Systems by Accretion via Science

Big Stars Resist Dieting via Science Now

There it is, indicated by the two lines. It looks like one enormous blob, but that's actually two stars. According to the ESO:

The two stars have masses of 82 and 83 times that of our Sun and rotate around each other in approximately 3.7 days. They are amongst the most massive stars known to astronomers.

Detailed observations of this intriguing pair have also shown that they are both Wolf-Rayet stars. These are massive stars nearing the end of their lives, expelling vast quantities of material as their final swansong. Observations made in X-rays have subsequently shown that streams of material from each star continually collide, creating a blaze of X-ray radiation.

The really cool part? This was taken from a ground observatory in Chile, not a satellite telescope. Amazing clarity for a ground-based system.

Claret-Colored Cloud with a Massive Heart [via ESO]

Collier’s editor Cornelius Ryan detailed von Braun’s plans for manned spaceflight across several issues of the magazine. Articles featured topics on manned lunar and Martian exploration, the potential for a space station, property and passage rights, and, of course, the ships themselves. The ships illustrated throughout the series were based on von Braun’s earlier designs, but he worked with the series’ artists to sketch out sleeker, sexier designs that would pop on the magazine’s pages.

New York auction agency Bonham’s will auction off von Braun’s Collier’s documents on Wednesday, which have a total estimated value of $15,000-25,000. You can see a sampling of the lot below, including a few of his vehicle designs and a letter from von Braun to “Connie” Ryan.

Von Braun Sketches to Be Auctioned [Space.com]
Space Expectations Slide Show [Scientific American]

According to Space.com:

The scientists deduced that whatever is driving the movements of the clusters must lie beyond the known universe.

A theory called inflation posits that the universe we see is just a small bubble of space-time that got rapidly expanded after the Big Bang. There could be other parts of the cosmos beyond this bubble that we cannot see.

In these regions, space-time might be very different, and likely doesn't contain stars and galaxies (which only formed because of the particular density pattern of mass in our bubble). It could include giant, massive structures much larger than anything in our own observable universe. These structures are what researchers suspect are tugging on the galaxy clusters, causing the dark flow.

"The structures responsible for this motion have been pushed so far away by inflation, I would guesstimate they may be hundreds of billions of light years away, that we cannot see even with the deepest telescopes because the light emitted there could not have reached us in the age of the universe," Kashlinsky said in a telephone interview. "Most likely to create such a coherent flow they would have to be some very strange structures, maybe some warped space time. But this is just pure speculation."

I'm ready for the strange structures, and for warped space time. Bring it on.

Mysterious New "Dark Flow" Discovered in Space [via Space.com]

Olson and his colleague Russell Doescher have made a name for themselves pioneering a field they call 'astroforensics.' Poring over historical texts (in this case Caesar's Commentary on the Gallic War), the two piece together bits of astronomical information that were recorded around the time of the event in question — phase of the Moon is a common one, as are the locations of Venus and the Sun, often recorded in paintings. In Shakespeare's "Hamlet" a 'bright star' is mentioned, and that was enough to get Olson thinking that it wasn't a star at all, but a Supernova that lit up the skies in 1572.

Knowing the phase of the Moon, Olson could calculate exact dates when, say, the tides would've been right in 55 BC for Caesar to make his landing near Dover. As it turns out, those same lunar and tidal conditions only present themselves once every few hundred years or so, and August 2007 was one of those dates. So Olson and company went to Dover, chartered a boat, and floated through the English channel, just as Caesar had done. Riding the same currents as the Romans, Olson showed that the evening of Caesar's arrival must have been August 22-23 in the year 55 AD rather than August 26-27, as generations of scholars before him had thought.

Caesar's landing was under duress — thousands of Celtic tribesmen greeted him with arrows and spears. But the Romans prevailed, and began an invasion that would lead to the formation of England.

Not all of Olson's work has as much historical import — he also likes following in the footsteps of Ansel Adams, and predicting when the waterfalls in Yosemite National Park will be moonlit as just the right angle so that their spray produces a rainbow — and he's calculated every time that will happen for the next two years. But CSI's got nothing on this guy, who needs nothing but the night sky to solve his cases.

Source: Sky & Telescope

Over at the New York Times, John Schwartz has seen the whole miniseries and says it has a not-so-subtle message: Will we continue to fund the space program? He writes:

Along with the drama of the Discovery programs and the overwrought musical score and the sometimes-portentous narration by [Gary] Sinise is, always, the message of the series: Human space exploration is worthwhile, even necessary. While critics of the manned space program argue that robots outstrip the abilities of humans for less cost and risk, the film puts forward Edward Weiler, the former chief scientist on the Hubble Space Telescope program.

The telescope was famously flawed upon its initial deployment and had to be repaired in orbit through a bold shuttle mission that involved five spacewalks of unprecedented complexity. “I can say unequivocally that if it wasn’t for the human space program, Hubble would be a piece of orbiting space junk,” he says.

NASA is now in the process of winding down the shuttle program; no flights are scheduled after 2010. What comes next, a new generation of spacecraft known as Constellation, will not be flying until 2015 at best. In the middle is a gap that will be filled by buying seats to the space station aboard the Russian Soyuz capsules. That period to come will test the nation’s commitment to spending the billions of dollars it takes to send humans into space and keep them safe from start to finish. It will test the notion that we need to send people into space at all.

These are topics worthy of a spirited national debate. And the Discovery Channel has put the argument on the table.

The miniseries will start Sunday at 9 PM on Discovery Channel.

50 Years of NASA's Home Movies [NYT]

According to a release from NASA:

"We found a clock that ticks slower and slower, and when it slows down too much, boom! The bomb explodes," says lead author Diego Altamirano of the University of Amsterdam in the Netherlands.

The bursts occur on a neutron star, which is the collapsed remnant of a massive star that exploded in a supernova. The neutron star belongs to a binary system that can be described as a ticking time bomb. Hydrogen and helium gas from a companion star spirals onto the neutron star, slowly accumulating on its surface until it heats up to a critical temperature. Suddenly, the hydrogen and helium begin to fuse uncontrollably into heavier elements, igniting a thermonuclear flame that quickly spreads around the entire star. The resulting explosion appears as a bright flash of X-rays.

These bursts, which can occur several times per day from the same neutron star, release more energy in just 10 to 100 seconds than our Sun radiates in an entire week. Put another way, the energy is equivalent to 100 fifteen-megaton hydrogen bombs exploding simultaneously over each postage-stamp-size patch of the neutron star's surface.

NASA satellite pins down time of explosions [Eurekalert]