Barnard 68 is a place in space where there is a big cloud of gas and dust. Think of it like a giant cotton ball floating in space. This cloud is very dark and doesn't let any light pass through it. That's why scientists call it a "dark nebula". It's kind of like when you put your hands over your eyes and you can't see anything because it's too dark.
But even though it's dark, scientists can still learn a lot about it. They use special tools to look at the cloud and figure out what's inside. They've found that there are lots of small particles called "dust grains" in Barnard 68. The dust grains are made up of things like carbon and silicon.
Sometimes, new stars can be born inside clouds like Barnard 68. But in this cloud, there aren't any new stars forming right now. Scientists think that maybe the cloud is too cold and dark for new stars to form.
Overall, Barnard 68 is a really interesting place in space because it's so dark and mysterious. Scientists keep studying it to learn more about the universe around us.