The surface of the sun is normally a roiling, super-heated hellscape. But Nasa images have revealed that the face of our star is looking ominously calm right now, prompting claims it’s reached a stage of its cycle called the solar minimum. During the minimum, there are significantly fewer sunspots and its magnetic field weakens, allowing cosmic rays from outside our solar system to rain down on Earth. This doesn’t tend to pose a threat to anyone here on Earth, but it’s risky for astronauts and satellites outside our atmosphere. The website Space Weather wrote: ‘The sun has been without spots for 16 consecutive days–a sign that Solar Minimum is underway. ‘Many people think Solar Minimum is uninteresting. Not so. ‘This phase of the solar cycle brings extra cosmic rays and long-lasting holes in the sun’s atmosphere.’ Huge solar eruptions could pose a serious threat to human civilisation
This solar slowdown often causes temporary cooling in Earth’s atmosphere Climate change deniers often hail this cooling as evidence that the heating of our world is about to go into reverse. Sadly, this is very unlikely to be true because the sun follows an 11-year cycle, meaning it will simply spring back to life in the coming years. However, once activity ramps up, the sun will be rocked by an increased number of gigantic ‘monster’ explosions, Nasa warned last week. Eruptions from the face of our star are called ‘prominences’ and cause vast amounts of superhot gas to shoot into space, often forming beautiful loops on the solar surface. During the solar minimum, the number of flares and sunspots is dramatically reduced. When the sun leaps back from its minimum after roughly 11 years, we’re likely to see more and more ferocious explosions on the sun.
Nasa warned: ‘After our Sun passes the current Solar Minimum, solar activity like eruptive prominences are expected to become more common over the next few years.’ The space agency has just released dramatic pictures of a ‘monster’ solar prominence recording by its Solar Dynamic Observatory in 2011, which shows what we should expect to see when the sun’s minimum reaches its end. Nasa wrote: ‘The dramatic explosion was captured in ultraviolet light in the featured time lapse video covering 90 minutes, where a new frame was taken every 24 seconds. ‘The scale of the prominence is huge – the entire Earth would easily fit under the flowing curtain of hot gas. A solar prominence is channelled and sometimes held above the Sun’s surface by the Sun’s magnetic field. ‘A quiescent prominence typically lasts about a month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. The energy mechanism that creates a solar prominence is still a topic of research.’ It’s feared a strong solar storm could bring civilisation to its knees (Image: Nasa) Solar eruptions cause solar storms which spark beautiful auroras – but a powerful tempest could bring civilisation to its knees (Image: Nasa) A prominence is not necessarily a threat to Earth, because they tend to loop into space and then fall back into the sun. But sometimes they can cause a ‘Coronal Mass Ejection’ which causes billions of tons of particles to gush outwards at high speed. These eruptions are generally only strong enough to cause problems for communications satellites or other spacecraft. Sometimes, however, they are much stronger and could be powerful enough to ‘impair’ human civilisation, Nasa warned earlier this year. The most famous Coronal Mass Ejection occurred in 1859 and caused a geomagnetic storm called the ‘Carrington Event’ as a pulse of charged particles bombarded Earth’s magnetosphere. If this happened today, the results would be devastating. In April, Nasa wrote: ‘The Carrington Event compressed the Earth’s magnetic field so violently that currents were created in telegraph wires so great that many wires sparked and gave telegraph operators shocks. ‘Were a Carrington-class event to impact the Earth today, speculation holds that damage might occur to global power grids and electronics on a scale never yet experienced.’