Van Dokkum

Normally, you wouldn’t be able to detect the light of an individual star in that pixel, but because these pulsating stars are so bright and the pulsation is so strong, we could see that about a quarter of the pixels of the image changed their brightness. They changed it because the pixels contain these pulsating stars.

It leads to a different way of looking at galaxies, where we always seen them as completely static in the sky, unchanging on human time scales, in fact, they are shimmering. They are shimmering constantly. Every pixel in the image is getting brighter and fainter and they are not constant at all, which is sort of a different way of almost thinking about the light in the universe.

For the age we thought - 10 billion years, we saw the exact number of stars that we expected, so, it turns out our models for this particular age are correct. Now, the next step is to look at younger galaxies and see if they have indeed stronger pulsations which we would predict.

We care about these stars because it’s our own future, the Sun will go through this phase in about 5 billion years so this phase of the evolution of stars has particular relevance to us.

We tend to think of galaxies as steady beacons in the sky, but they are actually shimmering due to all the giant, pulsating stars in them.

These pulsating stars are rare. All stars go through this phase b... by Van Dokkum

These pulsating stars are rare. All stars go through this phase but it doesn’t last that long.

Each of those pixels has like a million stars in them because the galaxies are so far away that we don’t see individual stars. We just see the combined light of all the stars in the galaxy.