Two bright comets will approach Earth in October

Comets are made up of ice, frozen gas and rock. As they travel close to stars like the Sun, their high temperatures cause them to shed gas and dust, creating distinctive tails.

Comet Lemmon shines in this image taken by the Zwicky Transient Facility on October 3. (Credit: Palomar Observatory)

Two new comets - C/2025 A6 Lemmon and C/2025 R2 SWAN - are approaching Earth and creating a spectacular show in the October sky. This is a rare opportunity to observe ancient objects from the edge of the Solar System, which are considered "time capsules" preserving primordial matter from the early days.

Astronomers have a great opportunity to observe two comets this month, SWAN and Lemmon. Both have long elliptical orbits around the Sun, so they only appear close to Earth for short periods.

As the comet's relative position to the Earth and the Sun changes as it moves through its orbit, the viewing angle from Earth also changes over time. Currently, Comet SWAN is visible in the early evening. Meanwhile, Comet Lemmon is visible near dawn, but will move into the evening hours over the next few days. For a better view, viewers should use binoculars or a telescope from an area with little light pollution.

Comet SWAN can be seen in this image taken by the Virtual Telescope Project on October 6. (Credit: Gianluca Masi)

As for their closest approach, SWAN will come within 38.6 million kilometers of Earth on October 20. Lemmon will come within 88.5 million kilometers of Earth on October 21. Both are long-period comets that were ejected billions of years ago from the cold, distant Oort Cloud. As they return closer to the Sun, they begin to shed gas and dust, creating a distinctive bright tail.

Ukrainian amateur astronomer Vladimir Bezugly discovered comet SWAN through images taken by the SWAN instrument on the Solar Wind ANisotropies spacecraft, a joint project between NASA and the European Space Agency to study the Sun.

Meanwhile, Lemmon was discovered by the Mount Lemmon Observatory in Arizona as part of the Catalina Sky Survey, a NASA-funded project that scans the night sky for near-Earth objects such as asteroids that could pose a threat to Earth.

Astronomy enthusiasts can try taking photos with their phones with a few seconds of exposure to capture this rare moment. Additionally, software such as Stellarium or KStars will help locate the comet in real time. If the weather is not favorable, you can still follow the livestream from the Virtual Telescope Project in Italy on October 20.

Mr. Quang

Source: https://vtcnews.vn/hai-sao-choi-ruc-sang-se-tien-gan-trai-dat-trong-thang-10-ar970364.html