According to the article "The brightness of 3I/ATLAS is rising sharply" on the public account "Starry Sky Astronomy", recently, some scholars used space-based solar observation equipment such as the GOES-19 satellite and the SOHO detector to discover that,Comet 3I/ATLAS's brightness rises sharply as it flies toward perihelion, and it is expected to reach approximately 9th magnitude near perihelion.

With this brightness, it would still be invisible to the naked eye on Earth without interference from the sun, but it could be observed with a small astronomical telescope.

The researchers found that 3I/ATLAS is significantly bluer in color compared to the Sun, indicating that it is releasing more gas near perihelion and therefore becomes brighter.

It was once reddish, indicating that its ejecta contained a higher proportion of dust, which is typical of comets.

When a comet approaches the sun, it will heat up, and the frozen material on the surface will sublimate into gas, wrapping the comet nucleus to form a coma and a tail. The gas will become brighter and brighter after being ionized by solar radiation.

3I/ATLAS not only has unique photometric changes, but its flight characteristics are also very outstanding.

Its speed through the solar system exceeds 210,000 kilometers per hour, and its perihelion speed exceeds 240,000 kilometers per hour. Its flight path is extremely straight, and its flight speed is the highest known among objects flying in the solar system.

In fact, the high speed of 3I/ATLAS shows that it has been flying in interstellar space for a long time. It has passed by stars one after another and nebulae after nebulae, continuously accelerating under the gravitational slingshot effect.

It is understood that 3I/ATLAS is the oldest known comet, which may have been born 7.6 billion years ago. It is also the largest known interstellar object that has entered the solar system, but its specific size has not yet been determined.

Data from the Hubble Space Telescope show that its maximum width is approximately 5.6 kilometers. On Earth, people may have to wait until December to see it with telescopes again.

However, in March 2026, 3I/ATLAS will pass by Jupiter, and the detectors in orbit around Jupiter will have the opportunity to observe it.