What is the significance of the discovery of Pluto's atmosphere?

The discovery of Pluto's atmosphere is significant because it provides important insights into the dwarf planet's composition, behavior, and evolution.

The atmosphere of Pluto was first detected in 1985, when astronomers observed a star being occulted by the planet. They noticed that the star dimmed and brightened more slowly than expected, indicating the presence of a tenuous atmosphere that was causing the star's light to be refracted.

Further observations by the New Horizons spacecraft, which flew by Pluto in 2015, revealed that the atmosphere is primarily composed of nitrogen, with smaller amounts of methane and carbon monoxide. The atmosphere is also highly variable, with changes in pressure and density occurring on timescales of hours.

These observations suggest that Pluto's atmosphere is closely linked to its surface and interior. For example, the presence of methane in the atmosphere may be an indication of ongoing geological activity, as methane is easily destroyed by sunlight and cosmic rays. Additionally, the variability of the atmosphere may be linked to seasonal changes on Pluto, which has an extremely elongated orbit around the Sun.

Overall, the discovery of Pluto's atmosphere has provided scientists with valuable information about this distant and enigmatic world, and has opened up new avenues of research into the outer reaches of our solar system.