Green Comet Making Closest Approach to Earth 去年發現綠色彗星ZTF 今最接近地球

A green comet that was detected in 2022 and named ZTF it will make its closest approach to Earth today.  Meanwhile, a telescope captured a blue spiral in the night sky and a teddy bear-like structure was found on the surface of Mars.

A telescope at the Mauna Kea Observatories in the U.S. state of Hawaii captured something astonishing on Jan. 18, a blue whirlpool swirling in a clockwise direction. It faded after spinning several times and the dot at the center disappeared. 

It started as a small dot that rapidly expanded until it formed into a spinning mass. It then faded away after about 15 minutes. Astronomers said it was likely related to a satellite launch by SpaceX, which was founded by Elon Musk. A similar sight was seen in New Zealand in June 2022. 

This time, the whirlpool was captured by the telescope not long after SpaceX's Falcon 9 rocket was launched from Cape Canaveral Space Force Station on Jan. 18. An article published on the website "Space.com" quoted an expert as saying these shapes happen when gas in the rocket engine's nozzles is at a higher pressure than the atmosphere and the gas is illuminated by sunlight. 

Meanwhile, a green comet named ZTF is set to make its closest approach to Earth on Feb. 1, coming within 42.5 million kilometers. The last time it approached Earth was 50,000 years ago, so seeing it is a once in a lifetime experience. ZTF was discovered in 2022 by Caltech's Palomar Observatory. Its coma has carbon-based molecules, which turn green when illuminated by sunlight. 

In related news, the University of Arizona shared on Jan. 25 a photo captured by NASA's Orbiter of a teddy bear-like formation on the surface of Mars. The university said the circular fracture pattern might be due to the settling of a deposit over a buried impact crater. The diameter of the "head" is about 2,000 meters, and the two "eyes" are craters. The "nose" and "mouth" are collapsed structures.

夏威夷毛納基亞山天文台望遠鏡18日拍攝到異象，一個藍色漩渦繞著中心點以順時鐘方向快速轉動，轉了幾圈後逐漸黯淡，中心的光點也消失在天際。

以一般的視角拍攝，看到的是一個光點快速移動，接著就出現清晰的螺旋，旋轉幾圈後就消失。整個過程歷時約15分鐘。天文專家研判和特斯拉總裁馬斯克創立的SpaceＸ發射衛星有關，因為像這樣轉動的奇異漩渦，去年6月也曾出現在紐西蘭。

SpaceX的獵鷹9號火箭在18日從佛州卡納維爾角發射升空後沒多久，毛納基亞山天文台就拍到漩渦。Space.com太空網站整理天文專家的說法，漩渦出現的原因，是火箭引擎噴口裡的氣體壓力高於大氣，當陽光照到這些氣體時，就會出現漩渦狀。

1顆名為ZTF的綠色彗星即將掠過天空，預計在2月1日最接近地球，距離約為4250萬公里。ZTF上次飛過地球是5萬年前，能看到它是一期一會的難得經歷。ZTF是2022年由美國加州巴洛馬天文台所發現，它的彗髮成分中具有碳基分子，被陽光照射後變成綠色，也是綠色彗星名稱的由來。

21世紀的火星探測陸續傳出重大成果，而最近的新發現更讓人會心一笑。執行火星高解析影像拍攝的亞歷桑納大學，25日分享一張火星照片，形狀看似泰迪熊的臉。圓形為地層裂縫形成的輪廓，直徑廣達2千公尺；眼睛部位是兩個坑洞，而狀似熊鼻和嘴巴的部分，是崩裂的地層構造。有網友逗趣留言，加上耳朵就更像熊的模樣。