Category Archive: Space

Coming to Terms with Turbulence

by Rosalind O’Brien

This Landsat 7 image of clouds off the Chilean coast near the Juan Fernandez Islands on September 15, 1999 shows a unique pattern called a "von Kármán vortex street." Study of this classic flow past a circular cylinder has been very important in the understanding of laminar and turbulent fluid flow that controls a wide variety of phenomena, from the lift under an aircraft wing to Earth's weather. Photo/NASA

“Turbulence is the graveyard of theories,” according to the renowned physicist Hans W. Liepmann, but scientists haven’t given up yet. Based on a turbulence lecture given by Prof. Mark Rast at the Laboratory for Atmospheric and Space Physics last Wednesday, it’s at least going to be a full and interesting graveyard.

Turbulence, in this context, is a specific physical phenomenon that describes the chaotic motion that can occur in fluids—both liquids and gases—when their molecules collide. Although many of us are unaware of it, turbulence occurs all around us, all the time.

The air behind an airplane and the water in an eddy are turbulent; they move chaotically at many scales, from those that humans can see and feel, all the way down to individual molecules.

Why does this matter? Rast provided plenty of reasons. Turbulence is why your car uses more gas when you go faster. When you’re driving, your car is slicing through the air in front of it. The faster you drive, the more difficult it is for air to converge immediately behind your car. This creates a sort of vacuum near your bumper, where air is moving chaotically, sucking your car backward ever so slightly. In other words, turbulence causes drag. Turbulence is therefore a very relevant concept in the automotive industry—it has literally shaped our cars. Continue Reading

Reverence for Apollo a Form of Necrophilia – Neil deGrasse Tyson

Neil deGrasse Tyson at Macky

Neil deGrasse Tyson has a simple message for people hung up on his ruling that Pluto is not a planet: Get over it. Tyson spoke to a packed house at Macky Auditorium on Wednesday, Feb. 15, 2012. (Photo/Beth Bartel).

by Brendon Bosworth

U.S. space exploration has atrophied and something needs to be done about it. This was the message from famed astrophysicist, and director of New York’s Hayden Planetarium, Neil deGrasse Tyson who delivered a scathing appraisal of the current state of space research to a packed house at CU-Boulder’s Macky Auditorium Wednesday night.

Since the Saturn V rocket launched the Apollo crews into space more than 40 years ago there has been very little progress in the space arena, explained Tyson, who padded around the stage quite comfortably on shoe-less feet and induced much laughter with his trademark blend of scholarly wit and stand-up comedian charisma.

“I call it Apollo necrophilia,” said Tyson, referring to the reverence people still hold for the antiquated technology that sent Neil Armstrong and Buzz Aldrin to the moon in 1969.

“As long as this continues to look awesome we have not advanced,” he said, pointing to a picture of the Saturn V on the screen behind him. There is no spaceship sitting on the next launch pad ready to take off, he said.

One reason that space exploration has failed to progress is that the space community can be considered a special interest group comprised of a few companies and organizations with a total membership of about 700,000 people, according to his calculations. The Sierra Club, Hanna Montana fan club and National Rifle Association each have more members than the space community, he said.

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Our Violent Star: Solar Storms and Space Weather

A solar flare bursts from a sun spot. Aug. 9, 2011. (NASA). (via www.nasa.gov)

By Sydney Kaufman

On a November night, when most of the world was sleeping, scientists and engineers at NOAA’s Space Weather Prediction Center in Boulder, Colorado, were watching live satellite pictures of the sun, looking for a bright flash that would tell them a strong solar storm was on its way, the effects of which could have been dramatic and expensive.

At that point, a tangled magnetic field on the sun’s surface was spinning towards the “kill zone,” the geographical location on the sun where an eruption would send energy and charged particles on a direct path to earth.

Luckily, the effects of this particular solar event on November 1, 2011, were minimal, resulting in only a brief radio blackout the following day. However, these NOAA scientists watch the sun 24/7 to ensure that when a blast of solar wind comes our way, we’ll be as ready as possible for the potential effects on communication signals, electrical power and the GPS systems many industries rely on. While the storm last November had little effect, a solar spot erupted last week and a minor geomagnetic storm is expected to peak today.

“The sun doesn’t give a hoot about where we are,” said Joe Kunches, an aerospace engineer at the Space Weather Prediction Center, during an interview in November. “It just goes about its business throwing off stuff and sometimes we happen to get in the way.”

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