3I Atlas just flew pas out sun and has revealed new details about its nature and makeup. In any comet’s life the most exciting time is when its approaches the sun and is at its shortest distance from Sun. We call this phase Perihelion. During this time comet gets to face full force of the sun and is continuously bombarded by radiation, heat and coronal mass ejections. Here is what has happened so far when 3I Atlas was closest to the Sun
- There was rapid change is brightness seen. The brightness increased some 400 times which is huge as most comets that pass by the sun only brighten up by 10 to 100 times.
- Light emitted by 3I Atlas was close to blue where normal expectation was it will be red due to coma of gas and dust.
- 3I Atlas started to experience non gravitational acceleration for the first time during its perihelion with the Sun. This is sort of expected as coma of the comet push around the object giving it non gravitational acceleration. The magnitude however is higher than expected.
- Its closest approach to the Sun was on October 29th 2025
- Data taken after closest approach shows seven distinct jets of gas going into space and are mostly pointing away from the sun. Couple of smaller jets are shooting directly into the sun which is not typical.
- Actual size of 3I Atlas is still debatable but its roughly estimated between 5km to 10km across and its more likely to be on the small side of the estimation range. This make 3I Atlas 20 times larger than Omua Mua.
