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Can we generate a way to interact with dark matter with current technology? – Leonardo S., age 13, Guanajuato, Mexico

That’s a great question. It’s one of the most difficult and fascinating problems right now in both astronomy and physics, because while scientists know that the elusive substance called dark matter makes up the majority of all matter in the universe, we’ve never actually observed it directly. Dark matter is so difficult to interact with because it’s “dark,” which means it doesn’t interact directly with light in any way.

I’m a physicist, and scientists like me observe the world around us mainly by looking for signals from different wavelengths of light. So no matter what type of technology scientists use, they run into the same issue in the hunt for dark matter.

It’s not completely impossible to interact with dark matter, though, because it can interact with ordinary matter in other ways that don’t involve light. But those interactions are generally very weak. What we call dark matter is really anything that we can see only through these weaker interactions, especially gravity.

One way that dark matter can interact with ordinary matter is through gravity. In fact, gravity is the main reason scientists even think dark matter exists at all.

For decades, scientists have been observing how galaxies spin and move throughout the........

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