NASA's Messenger spots giant space weather effects at Mercury

June 17, 2014 by Karen C. Fox
The yellow color shows the standing bow shock in front of Mercury. The signature of material flowing in a vastly different direction than the solar wind -- an HFA – can be seen in red at the lower left. Credit: NASA/Duberstein

(Phys.org) —The solar wind of particles streaming off the sun helps drive flows and swirls in space as complicated as any terrestrial weather pattern. Scientists have now spotted at planet Mercury, for the first time, a classic space weather event called a hot flow anomaly, or HFA, which has previously been spotted at Earth, Venus, Saturn and Mars.

"Planets have a bow shock the same way a supersonic jet does," said Vadim Uritsky at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "These hot flow anomalies are made of very hot deflected off the bow shock."

The results were published in the Journal of Geophysical Research: Space Physics on Jan. 15, 2014. To identify the presence of HFAs at Mercury, the team used observations from NASA's Messenger (short for Mercury Surface, Space Environment, Geochemistry, and Ranging) to detect the presence of two HFA signatures. The first measurement was of magnetic fields that can be used to detect giant electric current sheets that lead to HFAs. The second was of the heating of the charged particles. The scientists then analyzed this information to quantify what kind of turbulence exists in the region, which provided the final smoking gun of an HFA.

Not only is this the first sighting of HFAs at Mercury, but the observations help round out a picture of this type of in general. HFAs come in a variety of scale sizes – from around 600 miles across at Venus to closer to 60,000 miles across at Saturn. This study suggests that the most important factor for determining HFA size is the geometry and size of the planet's .

Explore further: Space weather: Explosions on Venus

Related Stories

Space weather: Explosions on Venus

March 5, 2012

In the grand scheme of the solar system, Venus and Earth are almost the same distance from the sun. Yet the planets differ dramatically: Venus is some 100 times hotter than Earth and its days more than 200 times longer. The ...

What will Voyager 1 discover at the bow of the solar system?

July 15, 2013

As the Voyager 1 spacecraft approaches the very edges of our solar system, space scientists await to see if it will discover the solar system's 'bow shock'; a theorized pile up of gas, dust, and cosmic rays, which accumulate ...

The Sun's ripple effect

July 30, 2013

A new study co-authored by Boston University astronomers indicates that a bow shock (a dynamic boundary between the Sun's heliosphere and the interstellar medium) is highly likely. These findings challenge recent predictions ...

The solar wind breaks through the Earth's magnetic field

June 10, 2014

Space is not empty. A wind of charged particles blows outwards from the Sun, carrying a magnetic field with it. Sometimes this solar wind can break through the Earth's magnetic field. Researchers at the Swedish Institute ...

Recommended for you

'Bathtub rings' suggest Titan's dynamic seas

July 28, 2015

Saturn's moon, Titan, is the only object in the Solar System other than Earth known to have liquid on its surface. While most of the lakes are found around the poles, the dry regions near the equator contain signs of evaporated ...

Born-again planetary nebula

July 28, 2015

Beneath the vivid hues of this eye-shaped cloud, named Abell 78, a tale of stellar life and death is unfolding. At the centre of the nebula, a dying star – not unlike our Sun – which shed its outer layers on its way to ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.