Posts Tagged ‘Science’

X-ray camera for lightning

In Read on March 15, 2011 at 7:24 am

Scientists have known for a while that lightning emits radiation but they haven’t known how, or from where.  To study the phenomenon researchers in Florida built an x-ray camera capable of taking ten million images per second:

Making a camera capable of taking such quick images was an achievement in and of itself, Dwyer emphasized.

“You can’t just go buy a camera and point it at lightning,” he said. “We had to make it.”

Because lightning moves blindingly fast, the camera was required to take ten million images per second.

One challenge in taking such fast pictures is storing the data. To do so, the x-ray detector had to take pictures at a relatively low resolution of 30 pixels, which produced images on a crude, hexagonal grid.

Lightning tower.  Photo courtesty Dustin Hill.

Lightning tower. Photo courtesty Dustin Hill.

Turns out almost all of the radiation is in the tip of the bolt.

Space shuttle launch from above

In Watch on March 10, 2011 at 7:19 am

Neil Monday is a software developer who was on a commercial flight out of Orlando National Airport on February 24th.  His window seat afforded him a spectacular view of the Space Shuttle Discovery’s final launch:

The video really gives you a sense of the power.  A parabolic path for a projectile seems so natural (Angry Birds!), but the shuttle just keeps going up.

Also, the shuttle coming up out of the cloud cover looks an awful lot like the Delta 2 rocket that we looked at last summer.

Via:  The Atlantic, via Cosmic Log

San Francisco Bay clouds

In Watch on March 1, 2011 at 9:56 pm

A gorgeous time-lapse video of clouds around the San Francisco Bay area:

1:36 looks like waves lapping at a shoreline.  Creator Simon Christen appropriately calls it “The Unseen Sea.”

Via: The Atlantic

White holes in the kitchen sink

In Read on February 18, 2011 at 7:23 am

Scientist Gil Jannes recently demonstrated that white holes exist directly below your kitchen tap:

Hydraulic jump with a mach cone.

Hydraulic jump with a mach cone.

Turn on your kitchen tap and the steady stream of water will spread out into a thin circular disc when it hits the sink. This disc has an unusual property: it is surrounded by a circular “lip”, where the height of the water changes suddenly.

This so-called hydraulic jump has puzzled physicists for at least a hundred years (John Strutt, otherwise known as Lord Rayleigh, published the first mathematical description of the phenomenon in 1914). These kinds of hydrodynamic problems are notoriously difficult to tackle.

In recent years, the study of hydraulic jumps has intensified. That’s because various physicists have pointed out that hydraulic jumps are examples of much more exotic objects: white holes, the time-reversed equivalent of black holes. (A white hole is a region that can emit waves and particles but which waves and particles cannot enter.)

This article has a bunch of things I didn’t know existed… the opposite of a black hole?  a hydraulic jump?  a mach cone?

Superhydrophobic carbon nanotube array

In Watch on February 17, 2011 at 7:23 am

Via Popular Science, here is a video from two researchers at Cal Tech.  It shows water droplets bouncing off a surface made of carbon nanotubes:

The surface is superhydrophobic, which is to say that it repels water to an extreme degree.  From the PopSci page:

Hydrophobic materials have all kinds of practical applications, from creating surfaces that never have to be cleaned to making supertankers and container ships glide more efficiently through the water.

Superior autobiographical memory

In Watch on February 8, 2011 at 7:18 am

Here’s a 60 Minutes story Lesley Stahl did in December on individuals who have the ability to recall every single day of their lives.  Each part is around 13 minutes long.  (You can also watch in a little bit better quality at the 60 Minutes website.)

Part 1

Part 2

“They can do with their memories what you and I can do about yesterday.”

Amazing, but it can also have a flip-side:

“Sometimes having this sort of extreme memory can be sort of isolating.”

I have a friend who has commented that the ability to let memories and ideas decay over time is more of a feature than a bug.  One of the researchers in the piece quotes American psychologist William James on this idea:

“If we remembered everything, we should on most occasions be as ill-off as if we remembered nothing.”

The five of them don’t seem to feel this way, though the piece does explore some of the drawbacks.

Also, at 60 Minutes Overtime there is an interesting behind-the-scenes look at how Lesley Stahl and her producer developed the story.  Stahl knew Marilu Henner as a friend, and knew that Henner had this gift.  When Stahl’s producer tried to sell her on the story about this super-rare condition, Stahl kept turning it down because she didn’t think it was that special.  “C’mon, it can’t be that rare.  I have a friend right over here who can do that too.”


Bacterial influence on the Gulf oil spill

In Read on February 2, 2011 at 7:08 am

Discover’s “Not Exactly Rocket Science” blog highlights a paper in which a researcher claims that the huge amounts of methane released into the Gulf of Mexico via last year’s oil spill have already disappeared:

With the well unsealed, substantial amounts of the gas were released into the gulf. This plume of dissolved methane should have lurked in the water for years, hanging around like a massive planetary fart. But by August, it had disappeared. On three separate trips through the gulf, John Kessler from Texas A&M University couldn’t find any traces of the gas above background levels. He thinks he knows why – the methane was eaten by bacteria.

Keep in mind we’re not talking about the crude oil we saw streaming from the busted pipe. But, wow, on the methane front, this is great news.

While this in no way diminishes the ongoing cleanup work that must be done, what we have here is an instance in the natural world of unexpected resiliency (first thing listed on TNF’s topic list!) in the face of what many feared was an unrecoverable situation.

Purpose of the appendix

In Read on January 28, 2011 at 7:12 am

This article is three years old, but the notion that the appendix is totally useless has somehow persisted, at least for me.

Researchers at Duke University think they have figured out the purpose of the appendix:

“Sometimes the flora of bacteria in the intestines die or are purged. Diseases such as cholera or amoebic dysentery would clear the gut of useful bacteria. The appendix’s job is to reboot the digestive system in that case.The appendix “acts as a good safe house for bacteria,” said Duke surgery professor Bill Parker, a study co-author. The location of the appendix — just below the normal one-way flow of food and germs in the large intestine in a sort of gut cul-de-sac — helps support the theory, he said.

The article also discusses the fact that the appendix may have lost its usefulness for people living in populations where diseases like cholera have been eradicated.  Hence the modern idea of the useless appendix (and the higher rate of appendicitis in developed countries).

Super slo-mo lightning strikes

In Watch on October 1, 2010 at 7:07 am

This video shows lightning strikes over Rapid City, SD, at 9000 frames per second.

Jason Kottke’s commentary:

The action across time scales displayed in this video is amazing. One strike hovers in the frame almost the entire time while other hundreds of other strikes flicker in and out in single frames.

We’re looking at less than half a second spread out over 1:32.  Per the YouTube description:

A preceding downward positive ground flash triggers upward leaders from seven towers, three of which are visible in the video.

The downward positive ground flash is the big boom on the left at 0:14.  The upward leaders from the towers start creeping up around 0:18.  By my count, the left-most tower then gets hit 18 times from 1:00 to the end of the video.  That’s 18 separate times over a tenth of a second if I’m reading the time code correctly.

Peat moss mushroom clouds

In Read, Watch on September 28, 2010 at 7:18 am

In a study published this summer, physicist Dwight Whitaker and his team describe how peat moss creates a vortex ring (like in a bomb blast’s mushroom cloud) to help propel their spores further.

This is the first time anyone has documented a plant creating a vortex ring, Whitaker said. In animals it is not that uncommon. Squid and jellyfish create vortex rings to propel themselves forward, and a healthy human heart creates a vortex ring between the left atrium and ventricle.

“This explains one of the wonders of the botanical world,” said biologist Joan Edwards of Williams College, an author on the paper. “It is amazing that such a simple plant came up with such a sophisticated system for propelling its spores.”

Follow the link for a couple brief HD videos of the explosions.

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