A surprise in the dark
Far down in the ocean, it is so deep that sunlight never reaches. It is colder than your freezer and darker than the darkest night.
While exploring this spooky place with an underwater robot, scientists saw something amazing: a small jellyfish that glowed with a soft blue light, like a tiny floating night-light.
How does it glow?
The jellyfish makes its own light using a special trick called bioluminescence. That is a long word that just means 'living light'.
Inside its body, two ingredients mix together and make a glow, a bit like how a glow stick lights up when you bend it. The jellyfish does this without any batteries at all!
Why make light down there?
Scientists think the glow helps the jellyfish stay safe. A sudden flash can surprise a hungry fish and give the jellyfish time to escape.
The light might also help it find food or send a 'hello' to other jellyfish in the dark.
Why this matters
We still know very little about the deep ocean — less than we know about the Moon! Every new animal we find helps us understand our planet a little better.
Who knows what else is glowing down there, waiting to be discovered?