It isn’t every night that a comet passes a galaxy. Last Thursday, though, binocular comet C/2018 Y1 (Iwamoto) moved nearly in front of a spiral galaxy of approximately the same brightness: NGC 2903. Comet Iwamoto was discovered late last year and orbits the Sun in a long ellipse. It last visited the inner Solar System during the Middle Ages, around the year 648. The comet reached its closest point to the Sun — between Earth and Mars — on February 6, and its closest point to Earth a few days ago, on February 13. The featured time-lapse video condenses almost three hours into about ten seconds, and was captured last week from Switzerland. At that time Comet Iwamoto, sporting a green coma, was about 10 light minutes distant, while spiral galaxy NGC 2903 remained about 30 million light years away. Two satellites zip diagonally through the field about a third of the way through the video. Typically, a few comets each year become as bright as Comet Iwamoto.
Have you ever seen a dragon in the sky? Although real flying dragons don’t exist, a huge dragon-shaped aurora developed in the sky over Iceland earlier this month. The aurora was caused by a hole in the Sun’s corona that expelled charged particles into a solar wind that followed a changing interplanetary magnetic field to Earth’s magnetosphere. As some of those particles then struck Earth’s atmosphere, they excited atoms which subsequently emitted light: aurora. This iconic display was so enthralling that the photographer’s mother ran out to see it and was captured in the foreground. No sunspots have appeared on the Sun so far in February, making the multiple days of picturesque auroral activity this month somewhat surprising.
What if you saw your shadow on Mars and it wasn’t human? Then you might be the Opportunity rover currently exploring Mars. Opportunity explored the red planet from 2004 to 2018, finding evidence of ancient water, and sending breathtaking images across the inner Solar System. Pictured here in 2004, Opportunity looks opposite the Sun into Endurance Crater and sees its own shadow. Two wheels are visible on the lower left and right, while the floor and walls of the unusual crater are visible in the background. Caught in a dust storm in 2018, last week NASA stopped try contact Opportunity and declare the ground-breaking mission, originally planned for only 92 days, complete.
NGC 2359 is a helmet-shaped cosmic cloud with wing-like appendages popularly called Thor’s Helmet. Heroically sized even for a Norse god, Thor’s Helmet is about 30 light-years across. In fact, the helmet is more like an interstellar bubble, blown as a fast wind from the bright, massive star near the bubble’s center inflates a region within the surrounding molecular cloud. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre-supernova stage of evolution. NGC 2359 is located about 15,000 light-years away in the constellation Canis Major. The remarkably detailed image is a mixed cocktail of data from broadband and narrowband filters that captures natural looking stars and the glow of the nebula’s filamentary structures. It highlights a blue-green color from strong emission due to oxygen atoms in the glowing gas.
Opportunity had already reached Perseverance Valley by June of 2018. Its view is reconstructed in a colorized mosaic of images taken by the Mars Exploration Rover’s Navcam. In fact, Perseverance Valley is an appropriate name for the destination. Designed for a 90 day mission, Opportunity had traveled across Mars for over 5,000 sols (martian solar days) following a January 2004 landing in Eagle crater. Covering a total distance of over 45 kilometers (28 miles), its intrepid journey of exploration across the Martian landscape has come to a close here. On June 10, 2018, the last transmission from the solar-powered rover was received as a dust storm engulfed the Red Planet. Though the storm has subsided, eight months of attempts to contact Opportunity have not been successful and its trailblazing mission ended after almost 15 years of exploring the surface of Mars.