Top 5 astounding astronomical discoveries in 2025.
As 2025 draws to a close, we look back at the year and, in the world of science, at the findings that have kept the world on its toes. Space aficionados, in particular, have had a thrilling time.
NASA has achieved a major observational milestone by using its Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission to continuously monitor Comet C/2025 R2 (SWAN) with unprecedented frequency. The spacecraft took pictures of the comet every four minutes for nearly 40 days, starting on 25 August and ending on 2 October. According to scientists, this may be the longest high-frequency monitoring of any comet to date.
Craig DeForest, principal investigator of the PUNCH mission at the Southwest Research Institute, claims that the mission’s success is due to the exceptional frequency of data collection rather than just the duration of observation. While other comets have been tracked for years at a once-per-day rate, the rapid-fire pace of PUNCH’s imaging offers scientists a far more detailed look at a comet’s behaviour during its journey through the inner solar system.
Advertisement
A time-lapse video created from hundreds of PUNCH images depicts the comet passing between two bright celestial objects: Mars above and Spica, the brightest star in the constellation Virgo, below.
Advertisement
Vladimir Bezugly, a Ukrainian amateur astronomer, discovered Comet SWAN in September. He noticed an unusually bright spot near the sun in publicly available images from the Solar and Heliospheric Observatory (SOHO). The comet reached its closest point to the sun, known as perihelion, just one day after its discovery. It was about 46.7 million miles (75.2 million kilometers) away at that time.
Initial observations showed a bluish-green coma surrounding the comet, the result of solar heat triggering sublimation — the direct transformation of ice into gas. Dust and gas were pushed out from the nucleus by solar winds, creating a glowing tail. The coma’s shape changed to an odd triangular ‘hammerhead’ shape by mid-September, a phenomenon frequently linked to comet fragmentation. The distorted shape, according to scientists, could be the result of outgassing from several fragments of a breaking nucleus, stretching what would typically be a rounded envelope of gas.
SWAN travelled alongside 3I/ATLAS, an interstellar object that attracted scientific interest due to its extra-terrestrial origin. 3I/ATLAS briefly showed up near the end of the PUNCH time-lapse, streaking beneath the comet from left to right.
Advertisement
