A Satellite flare (also called a Iridium flares or satellite glint) is a phenomenon caused by man-made satellite where the sunlight is reflected back to Earth. This results in a quick and bright "flare." Some flares can be up to 20 times brighter than Venus.
Iridium satellites are satellites that are used for telephones and other purposes such as navigation. Most of them are in a controlled orbit, so the flares from these satellites can be predicted. Computer programs can be fed the satellite's information and can predict a flare to an observer's location. The iridium satellite is known for having a weird shape. It has three door-sized antennas that occasionally reflects sunlight back to Earth. These can be very bright. So much so, that it can even be seen during the day. This annoys astronomers because it disrupts their observations.