The blue circle randomly picks a satellite to follow every few seconds. You can see some information about its location and speed (yes, that's kilometers per second) in the lower right corner.

The visual below shows the locations of 20% of the photos that were taken on January 25th, 2018 by Planet's satellites (the white circles) which are continuously circling the Earth.

The desktop version shows 100% of the photos.

In four years, Planet has flown on 18 successful launches and deployed 293 satellites successfully into low Earth orbit. With more than 150 satellites currently in orbit, Planet has the largest constellation of Earth imaging satellites in history.

As you may notice, the satellites are not always taking photos (or sending / "beaming" the data down to Earth). Parts of the landmass can also be missing due to complete cloud cover that day. See the Amazon, Central Africa, or Northern Australia for example.

A companion piece reveals more about the satellites themselves; the "doves", "RapidEyes", and "SkySats". Explaining their sizes, the numbers out there already and the types of images they capture. Check out the story here!