Featured Research

from universities, journals, and other organizations

Physicists Hear High-Tech Whistle While They Work

Date:
February 12, 2005
Source:
NASA/Jet Propulsion Laboratory
Summary:
It was music to the ears of physicists at the University of California, Berkeley, when they forced liquid helium-4 through thousands of tiny holes and heard a whistling sound. Why the big fuss about an odd sound? It seems this breakthrough might eventually lead to enhanced earthquake studies and more accurate navigation systems, including the Global Positioning System (GPS).

Dr. Richard Packard, left, and graduate student Emile Hoskinson, right, are shown with the cryostat insert, where the experiment was performed.
Credit: Photo courtesy of NASA/Jet Propulsion Laboratory

It was music to the ears of physicists at the University of California, Berkeley, when they forced liquid helium-4 through thousands of tiny holes and heard a whistling sound.

Why the big fuss about an odd sound? It seems this breakthrough might eventually lead to enhanced earthquake studies and more accurate navigation systems, including the Global Positioning System (GPS).

It all starts with one slippery liquid helium-4. Ultra-cold helium-4 becomes a superfluid, meaning it flows without friction. The scientists squashed it through an array of apertures 1,000 times smaller than the width of a human hair. The liquid whooshed faster and faster, until it reached a critical velocity. At that point, in a strange phenomenon, a microscopic quantum whirlpool dashed across each aperture, carrying away some of the helium-4's flow energy. This abruptly slowed the flow. The fluid repeatedly sped up and slowed down, creating vibrations that produced a whistling sound going from high to low.

A recording of the sound, called a quantum whistle, is available online at: http://www.nasa.gov/vision/earth/technologies/whistle.html.

"This whistle caught us by surprise," said UC Berkeley physics professor Dr. Richard Packard. "It turns out a single aperture will not make the whistle, because of random speed fluctuations. Our experiment shows all the flows through the holes are acting together, coherently, producing the whistle. We suspect it's like hearing thousands of crickets chirping in unison on a summer night."

Packard said this new phenomenon might lead to improved whistling superfluid navigation gyroscopes that detect extremely small rotational motion. As their motion changes, the whistle's volume would change. This would be especially useful on submarines or airplanes in regions where GPS signals are unavailable.

The GPS navigation system relies on knowing the state of Earth's rotation. Because weather and other factors affect Earth's rotation, the GPS system needs constant updating for accuracy. GPS gets its Earth rotation data from an array of radio telescopes distributed around the world. A very sensitive rotation sensor might complement the existing telescope array, providing data quickly and inexpensively.

Superfluid gyroscopes are devices that detect very small rotational motion. They use a specially-shaped, superfluid-filled vessel containing two aperture arrays; when the vessel rotates, the sound of the quantum whistle changes. This provides a telltale clue and allows for sensitive measures of the movements.

"This phenomenon may also permit scientists to develop very sensitive rotation sensors to measure small surface twisting signals created when an earthquake's vibrations travel through irregularities in the Earth's crust," Packard said. "In fact, we can take this concept even further. If seismologists can measure rotation signals from seismic activity on Mars, they might learn a lot about martian structure."

Packard and his colleagues have a history of hearing whistles while they work. Their experiments in 1997 and 2001, using liquid helium-3, produced a whistle. But the temperatures needed in those experiments were extremely low, just a few thousandths of a degree above absolute zero, which is almost one million times colder than average room temperature. Very few people are trained to work with such ultra-cold technology, which limits its potential applications.

Packard and graduate student Emile Hoskinson were especially excited because this latest phenomenon occurs at a relatively high temperature of 2 Kelvin, which is 2,000 times warmer than the previous helium-3 studies. This might make the technology available to more users with off-the-shelf cryocoolers.

This research was conducted under a grant from NASA and the National Science Foundation. The findings appeared in the January 27 issue of Nature. More information about Packard's research is online at http://www.physics.berkeley.edu/research/packard/.

JPL, a division of the California Institute of Technology, Pasadena, Calif., manages the Quantum Technology in Life Support and Habitation Program for NASA's Exploration Systems Mission Directorate.


Story Source:

The above story is based on materials provided by NASA/Jet Propulsion Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Jet Propulsion Laboratory. "Physicists Hear High-Tech Whistle While They Work." ScienceDaily. ScienceDaily, 12 February 2005. <www.sciencedaily.com/releases/2005/02/050211100217.htm>.
NASA/Jet Propulsion Laboratory. (2005, February 12). Physicists Hear High-Tech Whistle While They Work. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2005/02/050211100217.htm
NASA/Jet Propulsion Laboratory. "Physicists Hear High-Tech Whistle While They Work." ScienceDaily. www.sciencedaily.com/releases/2005/02/050211100217.htm (accessed July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins