NASA's STEREO (Solar TErrestrial RElations Observatory) research platform consists of two orbiting spacecraft that collect stereoscopic data about the sun and the eruptions of magnetized plasma during coronal mass ejections (CMEs). Last month, UFO buffs spotted a strange object in data acquired by STEREO, specifically what appears to be a wheel-shaped UFO. The footage made the rounds online (example above) spurring NASA to explain the anomaly. Turns out, it's… Venus. Bummer. From NASA:
Some people have noticed an odd shape, sort of a cross inside a circle, entering the field-of-view of the HI2 telescope on STEREO Ahead around February 20,2020. Eventually there is a cone shape that appears next to it. You can see the feature in question in this movie moving from right-to-left, just below the trapezoidal occulter on the right side of the image.
The answer lies on the exact opposite side of the image. At the same time as this strange-looking feature starts being visible, the very bright planet Venus enters the HI2-A field-of-view from the left. Notice that Venus and the feature stay in step almost exactly opposite each other across the middle of the detector. This is not a coincidence. The strange looking geometrical "object" is actually an internal reflection of the planet Venus within the telescope optics. This effect has been seen many times before. Here's a particularly striking example of internal reflections caused by the planet Earth as seen early in the STEREO mission, taken from our image artifacts pages.