Showing posts with label Magnetic Fields. Show all posts
Showing posts with label Magnetic Fields. Show all posts

Friday, April 7

Radio Signals From Space


(CNN) -- Astronomers have detected a repeating radio signal from an exoplanet and the star that it orbits, both located 12 light-years away from Earth. The signal suggests that the Earth-size planet may have a magnetic field and perhaps even an atmosphere.

Earth’s magnetic field protects the planet’s atmosphere, which life needs to survive, by deflecting energetic particles and plasma that stream out from the sun. Finding atmospheres around planets located outside of our solar system could point to other worlds that potentially have the ability to support life.

Scientists noticed strong radio waves coming from the star YZ Ceti and the rocky exoplanet that orbits it, called YZ Ceti b, during observations using the Karl G. Jansky Very Large Array of telescopes in New Mexico. The researchers believe the radio signal was created by interactions between the planet’s magnetic field and the star.

A study detailing the findings was published Monday in the journal Nature Astronomy.“We saw the initial burst and it looked beautiful,” said lead study author Sebastian Pineda, a research astrophysicist at the University of Colorado Boulder, in a statement. “When we saw it again, it was very indicative that, OK, maybe we really have something here.”

Magnetic fields can prevent a planet’s atmosphere from being diminished and essentially eroded away over time as particles release from the star and bombard it, Pineda said.

How strong radio waves occur
In order for the radio waves to be detectable on Earth, they must be very strong, the researchers said.  “Whether a planet survives with an atmosphere or not can depend on whether the planet has a strong magnetic field or not,” Pineda said.

Previously, researchers have detected magnetic fields on exoplanets similar in size to Jupiter, the largest planet in our solar system. But finding magnetic fields on smaller planets the size of Earth is more difficult because magnetic fields are essentially invisible.“What we’re doing is looking for a way to see them,” said study coauthor Jackie Villadsen, assistant professor of physics and astronomy at Bucknell University in Pennsylvania, in a statement.

“We’re looking for planets that are really close to their stars and are a similar size to Earth,” she said. “These planets are way too close to their stars to be somewhere you could live, but because they are so close the planet is kind of plowing through a bunch of stuff coming off the star. If the planet has a magnetic field and it plows through enough star stuff, it will cause the star to emit bright radio waves.”

YZ Ceti b only takes two Earth days to complete a single orbit around its star. Meanwhile, the shortest orbit in our solar system is the planet Mercury, which takes 88 Earth days to complete a lap around the sun.  READ MORE...

Friday, January 7

Early Disaster Warnings




Magnetic field information could provide earlier disaster warning to at-risk regions, potentially saving lives.

A new study finds the magnetic field generated by a tsunami can be detected a few minutes earlier than changes in sea level and could improve warnings of these giant waves.

Tsunamis generate magnetic fields as they move conductive seawater through the Earth’s magnetic field. Researchers previously predicted that the tsunami’s magnetic field would arrive before a change in sea level, but they lacked simultaneous measurements of magnetics and sea level that are necessary to demonstrate the phenomenon.

The new study provides real-world evidence for using tsunamis’ magnetic fields to predict the height of tsunami waves using data from two real events — a 2009 tsunami in Samoa and a 2010 tsunami in Chile — that have both sets of necessary data. The new study was published in AGU’s Journal of Geophysical Research: Solid Earth, which focuses on the physics and chemistry of the solid Earth.

The study confirms the magnetic field generated by a tsunami arrives ahead of sea-level change and that its magnitude can be used to estimate the tsunami’s wave height. How much earlier the magnetic field arrives depends on water depth, but in their results, the study authors found the early arrival time to be about one minute prior to sea level change over a 4,800-meter deep sea.

This information could provide earlier disaster warning if incorporated into tsunami risk models, potentially saving lives.



The aftermath of a 2010 tsunami in Chile, which was analyzed in a new study in JGR Solid Earth. Earlier warnings made possible by the study of tsunami-generated magnetic fields could better prepare coastal areas for impending disasters. Credit: International Federation of Red Cross and Red Crescent Societies