Apparently on Dec. 1st a video camera on board a NASA satelite captured a "UFO" during a solar flare, near Mercury (skip ahead to 33 seconds for the relevant footage).

Is it an alien spaceship? The shape is kind of odd looking, similar to the Enterprise of popular fiction.

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    The anomaly is large in comparison with Mercury and interacts with a Coronal Mass Ejection: the obvious candidate is that this is simply Mercury's magnetic field in action. Commented Dec 7, 2011 at 23:01
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    Would any of the voters like to explain their reasons for closing this? (When the community takes a different decision to the one I would take, I want to learn from it.) Agreed that this is a pitiful piece of UFO evidence, and the video author needs a lesson in Occam's Razor ("To explain an odd glitch on a video, you are positing (a) that intelligent aliens exist (b) that they have spacecraft that bring them within our solar system and (c) that they have a cloaking technology straight from a science fiction TV show? Could there be any other explanation?") But why is it not constructive?
    – Oddthinking
    Commented Dec 8, 2011 at 5:17
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    "Do you think that's an alien spaceship?" - That will likely solicit opinion, debate, arguments, polling, or extended discussion. I would vote to reopen if it gets revised and a notable claim that it is an alien craft is added.
    – Chad
    Commented Dec 8, 2011 at 14:25
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    As a complete side note: even if it was proven that it was a real object, I don't see how it's provable that's it an alien spaceship versus a man-made object... especially if it's the Enterprise :-)
    – Sklivvz
    Commented Dec 8, 2011 at 21:13
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    A couple of things: 1. I still don't really think it's a notable claim. We aren't here to debunk every whackjob video on youtube. Has this been widely reported? (now almost confirmed via Oddthinking's mX claim, which would make the re-opening okay in my mind) Is this a commonly held belief? 2. This question is still very difficult, or impossible, to answer in a scientific manner as it probably has to do with the minutiae of the instruments and methods of measurements used. It's not likely to be answered, as none of us are the scientists using these instruments.
    – John Lyon
    Commented Dec 8, 2011 at 22:35

3 Answers 3


No, it's not an alien spaceship. It's a ghost image of where Mercury was positioned the previous day.

According to NRL's Russ Howard, head scientist, and Nathan Rich, lead ground systems engineer, the mystery UFO is actually Mercury itself. It is simply a ghost of where Mercury was positioned the previous day, and was visible due to the way raw HI-1 telescope data is processed.

Howard and Rich explained that NRL scientists typically remove background light when processing such data in order to make the glow of a coronal mass ejection apparent against the bright glare from space. They identify what light is background light by calculating the average amount of light that entered individual camera pixels the day of the event as well as the day before. Light found in the pixels on both days is background light, and is then eliminated from the footage while the rest of the light is enhanced. This process is relatively easy for bodies like stars, but for those that are closer and move, such as planets, the process is a bit more challenging.

"When [this averaging process] is done between the previous day and the current day and there is a feature like a planet, this introduces dark (negative) artifacts in the background where the planet was on the previous day, when then show up as bright areas in the enhanced image," said Rich.

When this footage is reprocessed from a different day, the bright spot disappears due to different pixel values and removed light.

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    That's just explaining it away. Where's the evidence that the aliens haven't built a base on Mercury? {wink}
    – mellamokb
    Commented Dec 9, 2011 at 16:13
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    @mellamokb: There's no evidence that the aliens haven't built a base on Mercury because there are no records of them ever applying for building permits. ;-D Commented Dec 10, 2011 at 4:18
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    So it's a proof that ghosts are real??? ;-)
    – Sklivvz
    Commented Dec 10, 2011 at 10:37

This is not a cloaked UFO

This is a computer generated image that was produced in computer software rather unwanted but that is how the software was programmed.

In a normal night shot like this, the telescopes will see millions of stars. In fact there will be so many stars that you will not be able to see coronal mass ejection. In order to overcome that Nasa produces two images of the same spot (perhaps a day apart). The two images are overlapped on each other. If the white spots (stars) are exactly on the same place, the software blacks them out, if no such overlap exists, it leaves it as it is. This is again done to reinforce what we want to see, not what we know is already there. So all the stars are essentially blacked out.

When the two images are overlapped, the mercury has moved from its previous spot so it does not cancel any of its old image. There is some overlap with other stars though perhaps and some of it is blacked out. This is the reason there is this white spaceship which otherwise we could not see but we could see because special effects were used in the software and it is product of the software itself.

More explanation here, CNN Chad Mayer has explained it pretty well.


First, it's not a "video camera" - like most (all?) scientific spacecraft, STEREO can only take still images that can be stitched in a time-lapse movie in post-processing.

The image is indeed caused by the computer algorithm used for post-processing the images. The SECCHI team published the following explanation on their website.

In these HI-1 images, a daily median is used as the best near-real-time method to get CME enhancement. This results in dark spots from planets such as Mercury. When we derive the background, we do an interpolation between two daily median images. Since we make these images the day we receive them, we do not have a daily median for the next day, just the previous day. When the interpolation is done between the previous day and the current day and there is a feature like a planet, this introduces dark (negative) artifacts in the background where the planet was on the previous day, which then show up as bright areas in the enhanced image. Therefore, if (when) we re-generate these images, the bright artifact will go away because we have a daily median from the next day.

Please visit the link - the original text contains links that I haven't included here, and the page has an illustration of the effect and the code that produces it.

SECCHI also have a page with the unprocessed FITS images from that day. No UFO there. (You can easily find a FITS image viewer on the Internet. I think that the GIMP can open FITS files.)

Some additional reading, with a more layman-accessible explanation:

A Cloaked Alien Spaceship Orbiting Mercury? by Ian O'Neil on the Discovery News website.

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