Sedna, the most distant known object in the solar system, which opened in March 2004, continues to surprise astronomers.
Measurement of periodic brightness variations of this planetoid (or planet — astronomers have not come to a consensus) shows an unusually long rotation period — from 20 to 50 days.
Almost all the other little secluded objects in the solar system (such as comets and asteroids) turn around its axis in a few hours.
Only Mercury and Venus rotates more slowly than the recently discovered planetoid, but they behave so because of the tidal influence of the Sun.
Previously, astronomers have suggested that the slow rotation of the object associated with the presence of Sedna's moon.
However, until now no one picture, taken from orbiting telescopes, satellite Sedna could not be found. So perhaps it is not there.
This makes Sedna even more mysterious. However, there is a small chance that the satellite is shooting for the planet or in front of it.