It's been christened the "Marina receiver" after the newborn daughter of Flavio Gori, an Italian scientist who first suggested flying the receiver. The VLF receiver was donated to the Marshall Space Flight Center for this and possible future flights by the Goddard INSPIRE program. To hear what they sound like, click here.
To learn more about the physics of these emissions, click here. Other types of VLF radio emissions include tweeks, chorus, and spherics. They are caused by VLF radio emissions from lightning strokes that travel long distances along magnetic field lines.
That could set up plasma oscillations and trigger radio emissions."Ībove: This time-frequency plot (or dynamic spectrum) shows two whistlers, one at 9 minutes and one at 12 minutes. Because electrons are more mobile than protons, they move in to fill the void faster. "There's a low density wake right behind the meteoroid. "Meteoroids produce an ionized trail as they plummet through the atmosphere," explained Gallagher. Parents and Educators: Please visit Thursday's Classroom for lesson plans and activities related to this story.ĭennis Gallagher, a plasma physicist at the Marshall Space Flight Center, thinks that the VLF receiver might also pick up natural radio emissions from the Leonid meteors. Tweeks and whistlers are caused by more distant lightning, and sound like brief descending musical tones. "Spherics," which are caused by lightning strokes within a couple of thousand kilometers of the receiver, sound like twigs snapping or bacon sizzling on a grill. All three are impulsive bursts caused by distant lighting. The very low frequency (VLF) radio band is filled with exotic-sounding signals called spherics, tweeks and whistlers. That'll reduce spin and make it easier to pick up meteors and fireballs during the webcast."Īn important addition to this year's payload is an INSPIRE VLF radio receiver, which is sensitive to radio emissions below 10 kHz. This time I've added ball bearing swivels to the lines between the balloon and the payload package. The camera was sweeping across the sky pretty quickly, which made it hard to see faint meteors. One of the problems we encountered during that flight was the balloon spinning. The payload this time around will be similar to what we flew during the August Perseid shower. "We're going to be carrying a more sensitive camera than we did in 1998," said Ed Myszka, an engineer and radio amateur who built the balloon payload, "so the images could be even better than before. Sign up for our EXPRESS SCIENCE NEWS delivery Replays will be available after the flight. Web surfers can watch and listen to live transmissions from the balloon at between 01 EST, on November 18th. The balloon will carry a sensitive low-light CCD video camera to monitor the shower from an altitude of about 32 km (105,000 ft), far above any obscuring clouds or bad weather. Liftoff is scheduled for 0630 UT (0130 EST) on Thursday, November 18 from the Marshall Space Flight Center.
This year, with experts predicting an even bigger Leonid display, the meteor balloonists are planning another flight. It was recorded by a digital video camera carried aloft by a 3m weather balloon. Right: A short video segment showing a Leonid fireball as seen from the stratosphere in 1998. Researchers are still poring over the data. While the video camera on the balloon captured images of blazing fireballs, an aerogel collecting device may have captured bits of comet Tempel-Tuttle - the parent of the Leonid meteoroid stream. 1, 1999: Last year when flew a weather balloon to the stratosphere for a high altitude view of the Leonids, over one million people watched the live webcast or saw the replay the next day at.