UAE’s Hope Probe discovers mysterious new aurora on Mars

Scientists say the discovery left them 'scratching their heads'

HOPE MISSION MILESTONES - IN PICTURES: On July 16, 2014, the UAE announced its Mars mission would reach the planet in 2021, in time for the country's Golden Jubilee. Photo: Nasa

On May 8, 2015, during a glittering ceremony at Qasr Al Watan, Abu Dhabi, the name of the spacecraft and timeline of the mission is unveiled by Sheikh Mohammed bin Rashid, Vice President and Ruler of Dubai. Photo: Emirates Mars Mission

On November 12, 2017, at the Dubai Airshow, a prototype of the Mars spacecraft goes on display. Photo: Mohammed bin Rashid Space Centre

On January 5, 2020, Sheikh Mohamed bin Zayed, Crown Prince of Abu Dhabi and Deputy Supreme Commander of the Armed Forces, right, and Sheikh Mohamed sign the final piece of the Hope Probe before it is shipped to Japan for the launch. Photo: Wam

On January 21, 2020, a launch window between July 14 and August 3, 2020, is announced. The spacecraft would lift off from Japan’s Tanegashima Space Centre, aboard the HII-A rocket. On May 19, it is announced the first launch attempt would be made on July 15, 2020. Photo: Dubai Media Office

On April 5, 2020, Emirati engineers are sent, months in advance, to the launch site due to Covid-19. Some team members stay behind because only a limited number of people are allowed on site. Photo: Emirates Mars Mission

On April 25, 2020, the space orbiter arrives on Tanegashima island, 1,000 kilometres south of Tokyo. Photo: Emirates Mars Mission

The vehicle travelled in a special container to avoid damage and flew on one of the world's largest cargo planes. Photo: Emirates Mars Mission

Sarah Al Amiri, Minister of State for Advanced Technology and chairperson of the UAE Space Agency, and mission director Omran Sharaf, third left, discuss with engineers shipping the Hope probe to Japan. Photo: Mohammed bin Rashid Space Centre

The Hope probe arrives in Tanegashima island for a launch attempt on July 15, 2020. Courtesy: Yoshiaki Sakita

Heavy rainfall and strong winds delay the mission twice, on July 15 and July 17. Courtesy: Shoma Watanbe

On July 20, 2020, the Hope probe lifts off and begins its 493-million-kilometre journey to Mars. AFP

Sarah Al Amiri celebrates a successful take-off with launch provider Mitsubishi Heavy Industries. AFP

On July 22, 2020, the probe captures an image of Mars two days after it began its journey to the Red Planet. Sheikh Mohammed shared this image on Twitter. Photo: Sheikh Mohammed Twitter

On February 9, 2021, Sarah Al Amiri hosted an event at Dubai's Burj Park and gave live updates on the mission. Reuters

On February 9, 2021, mission director Omran Sharaf announces the Hope probe has successfully entered Mars orbit. Photo: Wam

Joyous scenes at the event in Burj Park. Christopher Pike / Reuters

Moments after the announcement, Sheikh Mohamed bin Zayed and Sheikh Mohammed bin Rashid thank staff at mission control in Dubai. Photo: Ministry of Presidential Affairs

On February 14, 2021, the spacecraft sends its first global image of the Red Planet. Photo: Emirates Mars Mission

On October 1, 2021, the UAE releases the first set of data collected by the mission, including images and science readings of the atmosphere and weather. Photo: Emirates Mars Mission

This image taken by the Hope probe’s ultraviolet spectrometer shows sunlight reflected from the extended cloud of atomic hydrogen gas that surrounds Mars. The sunlight is visible only as a dark disk hidden within the gas. Emirates Mars Mission

On January 1, a second set of data is released for free to the public. This image was enhanced by Andrea Luck and shows another cloudy day on the planet. The North Pole, Olympus Mons and Tharsis Montes are also visible. Photo: Hope Mars Mission / Andrew Luck

The UAE’s Hope spacecraft has made a landmark discovery of a new type of aurora on Mars.

Scientists with the mission are calling it the "sinuous discrete aurora", a huge, worm-like aurora that extends halfway around the planet.

Aurorae are colourful lights that appear on a planet when solar activity disturbs its atmosphere.

On Earth, the aurora borealis and aurora polaris – known as northern lights – happens when protons and electrons from solar wind hit particles in the atmosphere, causing colourful lights in the sky.

On Mars, however, because of its lack of a global magnetic field and localised crustal magnetic fields in the southern hemisphere, there are three types of aurorae – proton, diffuse and discrete.

But the latest discovery has left scientists puzzled, creating new questions about the interactions between Mars’ atmosphere, the planet’s magnetic fields and the solar wind.

“When we first imaged Mars’ discrete aurora shortly after the Hope probe’s arrival at Mars in 2021, we knew we had unveiled new potential to make observations never before possible on this scale, and we took the decision to increase our focus on these auroras,” said Hessa Al Matroushi, science lead at the Emirates Mars Mission.

“We can obtain nearly whole-disc, synoptic snapshots of the atmosphere to investigate atmospheric phenomena and interactions. It means we are seeing discrete auroral effects on a massive scale and in ways we never anticipated.”

In June, the spacecraft captured the most detailed observations of the discrete aurora in Mars’ night side atmosphere.

Aurorae in Mars’ night side atmosphere are extremely rare to capture. However, Hope has a higher possibility of imaging the phenomenon than any other spacecraft because of its unique elliptical orbit around the planet. It observes the night side on each of its 55-hour orbits of the planet.

What is the new aurora?

The sinuous discrete aurora is made up of long worm-like streaks of energised electron emissions in the upper atmosphere.

These extend many thousands of kilometres, stretching from the day side into the night side of Mars.

The aurora was imaged when the planet was experiencing the effects of a solar storm, which caused a more turbulent stream of solar wind electrons than usual. This allowed Hope to capture the brightest and most extensive aurora it has observed so far.

Dr Rob Lillis, a Hope mission team member at the University of California, Berkeley, described the discovery. "The sinuous discrete aurora was a shocking discovery that in many ways has us scratching our heads and going back to the drawing board," he said.

“We have ideas but no solid explanation for why we are observing intense aurora of this shape and at planetary scales.

“We now have the opportunity to re-examine prior observations of Mars by missions such as Maven and Mars Express to search for signatures that could flesh out Hope’s new observations and perhaps help us try and unpick quite what is happening here.”

The spacecraft arrived at Mars' orbit on February 9, 2021 to study the planet's dynamic weather conditions and atmosphere.

Since then, thousands of science images have been released, as well as data that is available free of charge online.