A picture is being circulated of a “huge sphere” passing in front of the sun that some claim shows a UFO. It almost certainly doesn’t.
“UFO fans fear it might be a ‘rogue planet’ on the loose in our solar system,” wrote the Metro, just one of a huge number of articles reporting the strange appearance. “Others fear it might be a huge Death Star-style UFO.”
But in fact the blue sphere appears just to be the consequence of a strange effect in the camera that took it. The images taken from Nasa’s SECCHI spacecraft – which spends its time watching the surface of the sun and sending the images from the Earth – are just an accident caused by the way the camera works.
Nasa has clarified that sometimes the sensor that processes those images before they are sent back to us can get overloaded, corrupting the images and making things appear that weren’t really there. As such, the blue sphere that UFO watchers are getting excited about is not simply less exciting than it seems – actually it never existed at all.
“On rare occasions, the SECCHI image processor onboard STEREO becomes overloaded, and produces corrupted images,” Nasa writes on the website devoted to the pictures. “Generally, these take the form of images from one telescope processed as if they were from another telescope.
Because the images from the Heliospheric Imager (HI) telescopes are built up from a large number of exposures added together, this sometimes results in “double exposures”, where data from several telescopes appear in the same image.”
It appears that the image actually shows two pictures of the sun blurring into each other. While that can’t be confirmed beyond doubt, it is a much more probable explanation and pictures resulting from the effect in the past look very similar to the new footage.
One thing that is definitely clear is that the image isn’t necessarily blue – in fact, it is a colourless photo that is run through a blue filter, so that everything would appear that colour. As such, many of the images of the sun that are shared from the telescopes appear blue, despite that not being the colour of the sun as we see it from earth.
It’s likely that a similar error could have caused the apparent outages that people have claimed happened after the object was spotted. Sometimes the spacecraft almost has the opposite error: it tries to take an image without actually opening the shutter, and so sees nothing at all.
“This generally results in a completely blank image,” Nasa writes. “Some coronagraph images built up from several exposures may show features in the corners of the image, as in this example.”
It’s also possible that the feed was turned off for investigation, or that it simply stopped working.
Read more at independent