Closest ever pictures of the Sun released by Nasa and European Space Agency

The Solar Orbiter spacecraft, a joint European Space Agency (ESA) and Nasa mission, has sent back never-before-seen images of the Sun’s surface.

The satellite took photographs of tiny solar flares called “campfires” near the surface of the star.

Its sensors gazed for 10 days at a time at light that is 13 times brighter than when looking directly at the Sun here on Earth.

The vehicle was only 77 million km away from the Sun, about half the distance between the Earth and the star.

The images were captured by the Solar Orbiter’s Extreme Ultraviolet Imager (EUI) when the craft was in its first perihelion – the point in its elliptical orbit closest to the Sun – between the orbits of Venus and Mercury.

No other spacecraft has been able to take such images so close to the Sun.

“The campfires are little relatives of the solar flares that we can observe from Earth, millions or billions times smaller,” said the principal investigator for the EUI instrument, David Berghmans of the Royal Observatory of Belgium.

However, scientists do not know yet whether the campfires are “nanoflares”, smaller versions of larger flares, or caused by some other mechanism of the nuclear fusion reactions that happen within the Sun.

Nanoflares are tiny sparks that heat the Sun’s corona, its outermost atmospheric layer. This can reach temperatures of more than a million degrees Celsius.

That is 300 times greater than the surface of the star, which is a comparatively chilly 5,500 degrees Celsius.

Despite decades of study, the mechanisms that heat the corona are still not fully understood, but such discoveries are vital in the study of solar physics.

It is possible the nanoflares could be the key to unlocking this mystery.

Yannis Zouganelis, Solar Orbiter deputy project scientist at ESA, said in a statement: “It’s obviously way too early to tell, but we hope that by connecting these observations with measurements from our other instruments that ‘feel’ the solar wind as it passes the spacecraft, we will eventually be able to answer some of these mysteries.”

“We are all really excited about these first images – but this is just the beginning,” said Daniel Muller, ESA’s Solar Orbiter project scientist. “Solar Orbiter has started a grand tour of the inner solar system, and will get much closer to the Sun within less than two years. Ultimately, it will get as close as 42 million km, which is almost a quarter of the distance from Sun to Earth.”

The temperatures of the campfires will be tracked using a tool called the Spectral Imaging of the Coronal Environment (Spice), which takes images using ultraviolet light.

“Spectroscopy is a powerful tool for the diagnostic of fundamental processes in hot plasmas. Each spectral line gives us a piece of the puzzle – combining information from all lines reveals the amazing complexity of the atmosphere,” said Dr Andrzej Fludra, the Spice Instrument Consortium lead.

The Solar Orbiter has ten sensors: six to monitor the Sun and its surroundings, and four to monitor the environment around the ship itself.

These include the Orbiter’s Solar Wind Analyser, which measures heavy charged atoms of carbon, oxygen, silicon, and iron in the solar winds from the Sun’s inner heliosphere.

By comparing the data between the sensors, scientists will also be able to better understand how solar winds are generated. Solar winds are charged particles sent from the Sun that can affect the entire solar system.

“Already our data are revealing shock waves, coronal mass ejections, phenomena called ‘switchbacks’ and fine-scale waves in the magnetic field that we are only able to see thanks to the extreme sensitivity of our instrument,” said Professor Tim Horbury from Imperial College London.

On occasion, the Sun pushes out a great number of particles into space. These are called “coronal mass ejections” and, when they hit the Earth’s magnetic field, they can cause a huge surge of electrical current.

On Earth, these events can disrupt and damage satellites, affecting people’s mobile phones, GPS signals, and electricity networks.

The largest one to hit the Earth happened in 1859 and caused telegraph wires to short out, sparking fires. If the same event happened today, it could potentially cause continent-wide blackouts and severely damage the electrical grid.

Such damage could take months or years to repair, at a cost of up to £300bn to the UK economy.

The Solar Orbiter itself was part of a combined effort by many countries: Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Italy, Ireland, Luxembourg, the Netherlands, Norway, Poland, Portugal, Spain, Sweden, Switzerland, and the United Kingdom, as well as Nasa in the United States.

It was built in the UK by Airbus Defence and Space, and launched from Nasa’s Cape Canaveral site in Florida on 10 February.

The Solar Orbiter will eventually get closer to the Sun than the planet Mercury, the solar system’s closest planet to the Sun.

Gravitational forces from Venus and Earth will be used to direct the craft. By November 2021, it is expected to be in operational orbit.