Because the viral photo of the April 8 solar eclipse taken by the James Webb telescope is fake

After the total solar eclipse on April 8 North America became viral a supposed photograph of the eclipse immortalized by the space telescope James Webb. The image is absolutely spectacular but it is absolutely fake. Not because it was created with an artificial intelligence tool: it is a real image, but it does not portray the April 8 eclipse (it is a retouched photo of the total solar eclipse seen in the USA in 2017 taken by the astrophotographer Sebastian Voltmer) and above all the telescope James Webb did not observe this phenomenon astronomical. But why wasn’t the most advanced space telescope ever built to observe the most important astronomical event of the year? At least there are three valid reasons: two related to its telescope location and one related to its sensor technology. This reminds us to always take cum grano salis viral content, which can sometimes be a real fast track for fake news.

Because James Webb couldn’t observe the eclipse

We must first consider the position of the James Webb Space Telescope. The instrument is positioned around a gravitationally stable point called Lagrangian point L2about 1.5 million km from Earth in the opposite direction – with respect to the Earth – to that in which the Sun is located.

Since the L2 point is always “behind” the Earth relative to the Sun, hence you cannot observe a solar eclipse: simply from this position the Earth is covering the Moon!

In reality James Webb is not exactly in L2 but is in orbit around this point, as shown in this NASA animation:

But even in the presence of a hypothetical alignment between the Sun, the Moon and the telescope, this eclipse would not have been visible at the moment it was on Earth! So it is completely unrealistic to even present a James Webb image of the solar eclipse.

But even if, paradoxically, NASA’s space telescope had been able to observe the eclipse, he could never see it completely as seen in the viral photo. This fact is also due to James Webb’s position, and in particular his own great distance from Earth.

In fact, let us remember that a total solar eclipse, like that of April 8, occurs due to an astronomical coincidence: from the position of the Earth, the solar disk and that of the Moon have almost the same apparent size. However, this is only valid from the Earth’s point of view: in James Webb’s position, in L2, the Moon appears decidedly smaller than the Sun (hence the apparent diameter of the Moon is about 25% of that of the Sun) and therefore not it is large enough to completely cover the solar disk and cause a solar eclipse! In short, James Webb could never have produced the viral eclipse photo because he could never observe it as total.

Last but not least, there is an important one technical question why the James Webb Space Telescope couldn’t have produced the photo that went viral, and it has to do with its equipment. The NASA telescope is meant for observe very faint objects, that is, with extremely low brightness. The telescope’s sensors are therefore a bit like our eyes when we have been in the dark for a long time: extremely sensitive to light. And what happens if after being in the dark for a long time we observe a source of intense light, such as a light bulb turned on by mistake? That’s right, we “burn our retinas”. For a sensitive instrument like James Webb, aiming for a solar eclipse would be the same thing: it would “burn out its sensors”, which would be saturated by light and therefore the image would be completely white.

A lesson on disinformation in social networks

An image from 7 years ago passed off as a photo of the Great North American Eclipse taken by a space telescope doesn’t seem like a serious matter, and it probably isn’t: it doesn’t cause damage and doesn’t hurt anyone (except the author of the original photo). However, it allows us to reflect on the risks of uncontrolled dissemination of unverified information on social media. As long as it’s a fake photo of an eclipse, nothing happens, but could we say the same for more delicate issues, related for example to health or politics? The same mechanism that makes an “impossible” photo go viral is also at the origin of the spread of fake news and disinformation, as sometimes happens with viral images or videos. This is why it is important today more than ever use social media responsiblypracticing healthy skepticism and avoiding spreading content that you are not sure of.