11
$\begingroup$

There ate two images below from the Parker Probe, one of Venus and the second from the Sun. The second one is a screenshot from a recent video (Youtube of Parker imagery while in solar corona).

In both you can see particles of some sort. What are they?

An image of Venus taken on July 11, 2020, by an instrument on NASA's Parker Solar Probe.

An image of Venus taken on July 11, 2020, by an instrument on NASA's Parker Solar Probe

Screenshot from the video from the Parker probe looking at the Milky Way when the Parker probe did a flyby at the sun, updated for clarity. enter image description here

Original poster's screenshot Original poster's screenshot

$\endgroup$
4
  • 1
    $\begingroup$ That's on a very sensitive exposure (enough to actually show the milky way, which is impressive for any imager, much less one inside the sun's corona) , so the lightsources are very faint. Possibly just outgassing from Parker's heatshield, shining in the sunlight? $\endgroup$ Dec 17, 2021 at 11:12
  • 1
    $\begingroup$ Guessing it's stuff ablating off the heatshield $\endgroup$ Dec 17, 2021 at 17:53
  • 1
    $\begingroup$ @AntonHengst I surely hope not, as it was present while passing Venus, and that is less than 1/80th the maximum heat load. $\endgroup$ Dec 17, 2021 at 19:23
  • $\begingroup$ @Kitty the ablation is caused by hypervelocity impacts from interplanetary dust, not by heat. $\endgroup$
    – giardia
    Dec 18, 2021 at 22:41

1 Answer 1

10
$\begingroup$

According to NASA:

Bright streaks in WISPR, such as the ones seen here, are typically caused by a combination of charged particles — called cosmic rays — sunlight reflected by grains of space dust, and particles of material expelled from the spacecraft’s structures after impact with those dust grains. The number of streaks varies along the orbit or when the spacecraft is traveling at different speeds, and scientists are still in discussion about the specific origins of the streaks here. The dark spot appearing on the lower portion of Venus is an artifact from the WISPR instrument.

To clarify the NASA statement, cosmic rays directly impact the detector and generate electrons to produce bright pixels in the image, leaving linear features as the charged particles traverse the detector material. Dust and ablated spacecraft material are flying around in space and reflecting sunlight, appearing as linear features due to their velocity relative to the spacecraft.

$\endgroup$
4
  • 2
    $\begingroup$ and especially How did Parker Solar Probe take what looks like 2D cross-sections of the solar wind in photographs; high contrast streaks in focus from volume effect? whose answer is complementary to yours. $\endgroup$
    – uhoh
    Dec 18, 2021 at 4:38
  • 2
    $\begingroup$ great answer dave, +1, and i added an explanation because NASA's em-dashes make it a little unclear that bright features in the image are produced in very different ways by CRs and dust/ablated material. $\endgroup$
    – giardia
    Dec 18, 2021 at 22:40
  • $\begingroup$ @uhoh Why are you promoting your own questions on other not related questions? Do you have a popularity problem? $\endgroup$ Dec 26, 2021 at 1:07
  • $\begingroup$ @KingsInnerSoul you can also flag my comments for deletion, applicable reasons include "no longer needed" and "other" followed by an explanation. I think that moderators are less likely to remove comments that have several upvotes (as mine do) indicating that others have found the comments helpful/valuable, but it's certainly another option. $\endgroup$
    – uhoh
    Dec 26, 2021 at 3:56

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.