Mars Express discovers aurorae on Mars

Jun 09, 2005
Mars Express discovers aurorae on Mars

ESA’s Mars Express spacecraft has for the first time ever detected an aurora on Mars. This aurora is of a type never previously observed in the Solar System.

Image: Terra Cimmeria is the area in the southern hemisphere of Mars where Mars Express has detected for the first time ever an aurora in the Red Planet. The aurora was detected at 177 degrees east and 52 degrees south. It is linked to anomalies in the crustal magnetic field, and it has a highly concentrated shape, making it unique in the solar system. Credits: NASA/ESA

Observations by the SPICAM instrument (SPectroscopy for the Investigations and the Characteristics of the Atmosphere on Mars) taken on 11 August 2004, revealed light emissions now interpreted as an aurora.
Aurorae are spectacular displays often seen at the highest latitudes on Earth. On our planet, as well as on the giant planets Jupiter, Saturn, Uranus and Neptune, they lie at the foot of the planetary magnetic field lines near the Poles, and are produced by charged particles – electrons, protons or ions – precipitating along these lines.

Aurorae have also been observed on the night side of Venus, a planet with no intrinsic (planetary) magnetic field. Unlike Earth and the giant planets, venusian aurorae appear as bright and diffuse patches of varying shape and intensity, sometimes distributed across the full planetary disc. Venusian aurorae are produced by the impact of electrons originating from the solar wind and precipitating in the night-side atmosphere.

Like Venus, Mars is a planet with no intrinsic magnetic field. A few years ago it was suggested that auroral phenomena could exist on Mars too. This hypothesis was reinforced by the recent Mars Global Surveyor discovery of crustal magnetic anomalies, most likely the remnants of an old planetary magnetic field.

SPICAM detected light emissions in the Southern hemisphere on Mars, during night time observations. The total size of the emission region is about 30 kilometres across, possibly about 8 kilometres high. Whilst the detected emission is typical for day-time, it must indicate the excitation of the upper atmosphere by fluxes of charged particles – probably electrons – if observed during night-time.

By analysing the map of crustal magnetic anomalies compiled with Mars Global Surveyor’s data, scientists observed that the region of the emissions corresponds to the area where the strongest magnetic field is localised. This correlation indicates that the origin of the light emission actually is a flux of electrons moving along the crust magnetic lines and exciting the upper atmosphere of Mars.

SPICAM observations provide for the first time a key insight into the role of the martian crustal magnetic field in producing original cusp-like magnetic structures. Such structures concentrate fluxes of electrons into small regions of the martian atmosphere. Eventually, they induce the formation of highly concentrated aurorae whose formation mechanism – a localised emission controlled by anomalies in the crust’s magnetic field – is unique in the Solar System.

The martian aurora was observed in the Mars region corresponding to 177 degrees east and 52 degrees south.

These results appear in the 9 June issue of the scientific journal Nature.

The authors of the findings are: J-L. Bertaux, SPICAM Principal Investigator, F. Leblanc, E. Quemerais (Service d’Aeronomie du CNRS/IPL, France), O. Witasse (European Space Agency – Noordwijk, The Netherlands), J. Lilensten (Laboratoire de Planetologie de Grenoble, France), S.A. Stern (Southwest Research Institute, Colorado, USA), B. Sandel (Lunar and Planetary Laboratory, University of Arizona, USA), O. Korablev (Space Research Institute-IKI, Moscow, Russia).

Source: ESA

Explore further: Radar guards against space debris

Related Stories

Rosetta and Philae at comet 67P/Churyumov-Gerasimenko

Jun 22, 2015

Rosetta has been exploring comet 67P/Churyumov-Gerasimenko since summer 2014. In November 2014, the Philae lander landed on the surface of the comet. The first measurements by the scientific instruments allow ...

MAVEN results find Mars behaving like a rock star

Jun 22, 2015

If planets had personalities, Mars would be a rock star according to recent preliminary results from NASA's MAVEN spacecraft. Mars sports a "Mohawk" of escaping atmospheric particles at its poles, "wears" ...

A new and game-changing magnetoresistance

Jun 16, 2015

More than 150 years ago, William Thomson, later Lord Kelvin, discovered the magnetoresistive effect. Today, this finding enables sensors to measure the rotational speed of a car wheel, and is also used in ...

Using meteorite impacts to study seismic waves on Mars

Jun 08, 2015

(—Earth scientist Nick Teanby with the University of Bristol in the U.K. has come up with a novel way to measure seismic waves traveling through the under-surface of Mars—use data from meteorite ...

Recommended for you

Radar guards against space debris

42 minutes ago

Space debris poses a growing threat to satellites and other spacecraft, which could be damaged in the event of a collision. A new German space surveillance system, schedu- led to go into operation in 2018, will help to prevent ...

Why we need to keep adding leap seconds

2 hours ago

Today at precisely 10am Australian Eastern Standard time, something chronologically peculiar will take place: there'll be an extra second between 09:59:59 and 10:00:00.

Helping Europe prepare for asteroid risk

3 hours ago

Each year, astronomers worldwide discover over 1000 new asteroids or other space rocks that could strike our planet. And if one is spotted heading towards Earth, experts working in ESA and national emergency ...

Image: Increasingly active Comet 67P

3 hours ago

On 13 August 2015, Comet 67P/Churyumov–Gerasimenko will reach its closest point to the Sun along its 6.5-year long orbit. It will be around 185 million km from the Sun at 'perihelion', between the orbits ...

User comments : 0

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.