A recently discovered green comet will soon zip by Earth for the first time in 50,000 years. It was last visible in the night sky during the Stone Age.

Discovered on March 2, 2022, by astronomers using the Zwicky Transient Facility’s wide-field survey camera at the Palomar Observatory in San Diego County, California, the comet made its closest approach to the sun Jan. 12, according to NASA.

Named C/2022 E3 (ZTF), the comet has an orbit around the sun that passes through the outer reaches of the solar system, which is why it’s taken such a long route — and long time — to swing by Earth again, according to The Planetary Society.

The icy celestial object makes its closest pass by Earth between Feb. 1 and Feb. 2 (today), around 42 million kilometers to 44 million kilometers away, according to EarthSky.

Even during its closest approach, the comet will still be more than 100 times the moon’s distance away from Earth, according to EarthSky.

As the comet nears Earth, observers will be able to spot it as a faint green smudge near the bright star Polaris, also called the North Star. Comets reflect different colors of light due to their current positions in orbit and chemical compositions.

Early morning skies, once the moon has set after midnight for those in the Northern Hemisphere, are optimal for viewing the comet. The space object will be more difficult to see for those in the Southern Hemisphere.

Depending on its brightness, C/2022 E3 (ZTF) may even be visible to the unaided eye in dark skies, but binoculars or a telescope will make the comet easier to see.

The comet can be distinguished from stars by its streaking tails of dust and energized particles, as well as the glowing green coma surrounding it.

The coma is an envelope that forms around a comet as it passes close to the sun, causing its ice to sublimate, or turn directly to gas. This causes the comet to look fuzzy when observed through telescopes.

After passing by Earth, the comet will make its closest approach of Mars on Feb. 10, according to EarthSky.

If clouds or inclement weather get in the way of skywatching, The Virtual Telescope Project will share a livestream of the comet in the skies above Rome.

Words to Learn 相关词汇

【最佳的】zuìjiā de optimal best or most favorable

【双筒望远镜】shuāngtǒng wàngyuǎnjìng binoculars an optical instrument with a lens for each eye, used for viewing distant objects

最近发现的一颗绿色彗星将很快掠过地球。这是它5万年来首次路过，它上一次出现在夜空中还是石器时代。

美国宇航局称，天文学家2022 年3月2日在加利福尼亚州圣地亚哥县帕洛玛天文台发现了这颗彗星，当时他们使用了兹威基瞬态研究设施的宽视场测量相机。彗星1月12日通过近日点。

这颗彗星被命名为 C/2022 E3（ZTF），

根据行星协会的说法，其轨道围绕太阳穿过太阳系的外围，这就是为什么它经过如此漫长的路线 —— 和时间 —— 才能再次掠过地球。

据EarthSky网站称，这个冰冷的天体在2月1日至2月2日(今天)之间最接近地球，距离地球约4200万公里至4400万公里。

该网站称，即使在最接近地球的时候，这颗彗星和我们之间2的距离比月球与地球之间距离的100倍还要远。

当这颗彗星接近地球时，观测者将能够在明亮的恒星北极星附近发现它是淡绿色的身影。彗星在轨道上的位置和它的化学成分决定它反射不同颜色的光。

对于北半球的人来说，一旦月亮在午夜后落下，清晨的天空是观看彗星的最佳选择。南半球的人更难看到它。

根据其亮度，C/2022 E3（ZTF）甚至可以在黑暗的天空中肉眼观测，但双筒望远镜或天文望远镜能更好地观测彗星。

这颗彗星与恒星的区别在于它由尘埃和带电粒子形成的尾巴，以及它周围发光的绿色彗发。

彗发是彗星靠近太阳时在彗星周围形成的包裹层，太阳的光热让彗星中的冰升华，即直接变成气体。这让彗星在通过望远镜观察时显得模糊。

据EarthSky报道，在经过地球后，这颗彗星将在2月10日最接近火星。

如果云层或恶劣天气妨碍了观测，虚拟望远镜项目将从罗马上空直播这颗彗星路过地球。

(SD-Agencies)