A former NASA analyst has taken to TikTok to explain the (hopefully obvious) reason why photos of our galaxy – the Milky Way – are not real.
When asked “How do we take pictures of the Milky Way when we are in it?” science communicator and former NASA space analyst Alexandra Doten explained that we simply don’t have any pictures of the Milky Way.
“Every complete picture of the Milky Way is an illustration,” she explained in the video. “We can’t see the Milky Way like that, and I don’t think people ever will.”
The reason for this is simple: we have never been able to view the Milky Way from any vantage point other than the edge of a spiral arm of our galaxy.
Think of it like the Earth, only with a few added complications. We’ve known the shape of the Earth for a long time because we’ve mapped its surface, studied the motions and shapes of the planets and stars, and carefully measured the Earth’s gravity at various points. By doing this, we’ve determined the shape of the Earth, including the fact that it’s not perfectly round. But we could never have a complete picture of the Earth until we left it and were far enough away to photograph it in its entirety.
The first image of the entire Earth from space was taken in 1972, when astronaut Ron Evans or Harrison Schmitt took a photo aboard Apollo 17 en route to the Moon. This was the first time that the trajectory of an Apollo mission allowed such a photo to be taken, and the result was the iconic “Blue Marble” image.
Leaving the galaxy far enough to photograph it is a completely different endeavor for a species that has not yet left the solar system.
“To obtain (images of the Milky Way), a spacecraft would have to fly either up or down out of the Milky Way’s disk, traveling incredibly long distances,” explains Doten.
But that doesn’t mean we don’t know what the Milky Way looks like. Most of the objects you see when you look up into the night sky are stars in our own galaxy that we can map. We can also see a large part of the Milky Way in the night sky and from that we can map the stars in it and get an idea of what it looks like. Doten compares it to trying to create an image of a Ferris wheel you’re currently riding on.
We can see and image enough objects in our galaxy – including the supermassive black hole at its center – to get a pretty good idea of what it looks like. By mapping the stars in it and looking at their shape, we can see that we are in the spiral of a barred spiral arm galaxy. Seeing other galaxies similar to our own also helps, just as Isaac Newton realized that the Earth has a bulge by observing the bulge of Jupiter.
The more we observe it, the better we can figure out what’s going on, and also look for collisions with other galaxies. But we’ll probably never see the Milky Way from far enough away to take a real photo of its beauty, and certainly not in our lifetimes or for many, many generations to come.
