A pair of satellites have recorded for the first time a massive explosion blasting its way from the depths of the Sun. The solar tsunami resembled a tidal wave on Earth but travelling at speeds of well over half a million miles an hour.
Such blasts can hurl electrically charged material at the Earth, threatening communications satellites, power grids and even the lives of astronauts.
The tsunami bursting out of the Sun’s lower atmosphere – called a coronal mass ejection – was captured by Nasa’s twin Stereo spacecraft which produce 3D images of our home star.
The event, which happened on May 19 last year, will be reported to the National Astronomy Meeting in Belfast today. The observations were made by a team from Trinity College, Dublin. Yesterday we told how another team has mapped in detail, the solar corona.
Team member David Long said: “The energy released in these explosions is phenomenal, about two billion times the annual world energy consumption in just a fraction of a second. In half an hour, we saw the tsunami cover almost the full disc of the Sun, nearly a million kilometres away from the epicentre.”
The Stereo instruments monitor the Sun at four wavelengths, which allowed observers to track the tsunami as it travelled through different layers of the solar atmosphere. But tracking its path has raised new questions for astronomers to answer.
Fellow researcher Peter Gallagher said: “To our surprise, the tsunami seems to move with similar speed and acceleration through all the layers. As the chromosphere is much denser than the corona, we’d expect the pulse there to drag. It’s a real puzzle.”
Despite this, the team hope that results from Stereo and other sun-watching satellites will soon help them to identify the cause of coronal mass ejections.
Picture: A single Stereo image of another explosion on the Sun. (Nasa).