You should read about the Landsat 7 ETM+ SLC-off data
This refers to all Landsat 7 images collected after May 31, 2003, when the Scan Line Corrector (SLC) failed. These products have data gaps, but are still useful and maintain the same radiometric and geometric corrections as data collected prior to the SLC failure.
I showed this question to a friend who designs and builds satellite imagers. Here's what he wrote:
Can a satellite see a rainbow?
Will it look like what you would normally think of as a rainbow – – an arc?
Not really. The arc would be huge. Hundreds of kilometers in diameter.
Are those dim colored lines likely to be a rainbow?
I strongly doubt it. ...