Correct, That is the headline, which is true, and not as clickbaity
The faux headline of "We'Ve NeVeR LeFt tHe AtmOsPheRe" (same as the one that OP wrote) is more misleading, and I'll explain why.
A headline saying "we've never left earth's atmosphere" is terrible clickbait, because for most people's understanding, the atmosphere does not go past the moon, so now a moron or a child walks away from the title of an article thinking that we've never gone to space or landed on the moon.
However, the headline "earth's atmosphere goes past the moon" is still true, but the atmosphere that reaches further is so thin it's barely even perceived. Technically, the moon and surrounding space are still in the earth's atmosphere, so from this fact, we can technically say that we've never left earth's atmosphere, but the required explanation of why that sentence is true needs to come first. The clickbaity "We've never left earth's atmosphere" line is literally the last line of the article, after all of the explanation about what the scientists have found.
Because yesterday it wasn't known to have existed. Now that we have discovered it, we assign a definition to what it is. In this case, an extension of our atmosphere.
It's not as though we have always known this was here and now we suddenly decide it's part of the atmosphere, but now we're able to detect and measure it, as we already have been able to our previously known atmosphere.
Correct, That is the headline, which is true, and not as clickbaity
The faux headline of "We'Ve NeVeR LeFt tHe AtmOsPheRe" (same as the one that OP wrote) is more misleading, and I'll explain why.
A headline saying "we've never left earth's atmosphere" is terrible clickbait, because for most people's understanding, the atmosphere does not go past the moon, so now a moron or a child walks away from the title of an article thinking that we've never gone to space or landed on the moon.
However, the headline "earth's atmosphere goes past the moon" is still true, but the atmosphere that reaches further is so thin it's barely even perceived. Technically, the moon and surrounding space are still in the earth's atmosphere, so from this fact, we can technically say that we've never left earth's atmosphere, but the required explanation of why that sentence is true needs to come first. The clickbaity "We've never left earth's atmosphere" line is literally the last line of the article, after all of the explanation about what the scientists have found.
This isn't scope creeping though. The geocorona is being considered as an extension of earth's atmosphere.
Because yesterday it wasn't known to have existed. Now that we have discovered it, we assign a definition to what it is. In this case, an extension of our atmosphere.
It's not as though we have always known this was here and now we suddenly decide it's part of the atmosphere, but now we're able to detect and measure it, as we already have been able to our previously known atmosphere.