Why does a bright star hide the planets next to it?

Picture lying on cool grass on a clear night, looking up at the twinkling stars. Many of those faraway stars have planets circling them, just like Earth circles our Sun. Yet even people with giant telescopes find those planets hard to spot.

The planets are right there beside their stars, but the bright star seems to hide them. So why does a bright star hide the planets next to it? Let's follow the light and find out.

A star is a giant ball of gas, so hot that it glows and makes its own light. It sends that light out in every direction, all the time. That is why we can see stars shining from far, far away.

A planet does not glow like a star. It can only reflect a little of its star's light, which means bouncing the light back, the way a spoon flashes when sunshine hits it. That bounced light is the only way a planet shines.

Because a planet can only reflect light, it looks much dimmer than its star. A star shines more than a million times brighter than the planets around it. Picture a tiny firefly floating beside a huge stadium light.

Planets circle close to their star, and the star sits unbelievably far from us. From Earth, the gap between a planet and its star looks thinner than a hair. The planet seems squeezed right up against the star.

When we look at a bright star through a telescope, its light spreads out into glare, which means a dazzling glow that spills around a strong light. That glare stretches a little way out from the star, past the spot where the planet sits. So what do you think happens to the planet's faint light inside that glow?

The planet's tiny bit of reflected light disappears into the glare, like a firefly beside that stadium light. Our eyes and our telescopes catch only the bright star, and the planet seems to vanish. It is still there, circling quietly, hidden inside the glare.

Reflect and glare. A bright star shines more than a million times brighter than its planets, so its glare spills over the planet sitting close beside it and covers the faint light the planet can only reflect.

Next time you see a star twinkling, you can smile and wonder about the quiet planets hiding in its glow.