Skywatchers in the northern hemisphere have been graced by the presence of a green comet bursting with light that keeps growing brighter as it nears the sun.
Named PanSTARRS (C/2017 S3), the comet is expected to reach its closest point to the sun, at which point it may grow even brighter and become visible to the naked eye.
Green Comet Exploding In Night Sky
The remarkable celestial sight was first spotted on July 2 by Michael Jäger of Austria, an amateur astronomer who has logged more than 500 observations of comets to date.
Just two days before that, the comet registered a magnitude of 12.5. This means it was less visible than the faintest stars when seen through a small telescope.
However, the comet suddenly increased in brightness over the next couple of days, eventually reaching a magnitude of 9.5. Anyone with a pair of binoculars that has a 50-millimeter lens and a magnification of up to 10 times can see the comet from their backyard.
Continuous observation of PanSTARRS (C/2017 S3) reveals the green light is becoming brighter, a telltale sign that the icy comet's boiling gases exploded as it approached the sun.
"The gas cloud around the comet's nucleus is about 4 arc minutes wide," Jäger says.
This is roughly equivalent to around 160,000 miles, or nearly two times the size of Jupiter. The size of the dust cloud alone makes it easy enough for anyone with a telescope to watch the comet as it streaks across the northern skies.
Best Times To View
PanSTARRS (C/2017 S3) will reach its perihelion, or the closest point to the sun, on Aug. 16. It will be prowling just within the orbit of Mercury, where its nearness to the sun will make it a prime target for a blast of solar radiation.
However, its proximity to the sun will make it almost impossible to be seen in mid-August. Astronomers say the best times to spot the green comet in the northern hemisphere are on the first few days of the month, particularly on Aug. 4 and 5.
The comet is currently found in the direction of Camelopardalis, a large constellation in the northern sky resembling a giraffe. It is expected to pass through Auriga north of the celestial equator until it reaches Gemini on Aug. 4 to 5. AAfterward it will travel toward the sun where it will be hidden from view until it makes its way back.
In the southern hemisphere, there is less chance to spot the comet, although it may be visible for a brief period before sunrise of Aug. 15 after it turns away from the sun.
There is no knowing what will happen to the comet once it reaches the sun, though. Astronomers say it could reach magnitude 4, making it bright enough to be seen by the naked eye. It is also possible that the blast of radiation from the sun could elicit more explosions, rendering the comet even brighter in the night sky.
First-Time Visitor From The Oort Cloud
The green comet was first seen soaring over the Earth on Sept. 23, 2017, by the PanSTARRS telescope at the Haleakalä Observatory in Maui, Hawaii. The goal of the project is to find near-Earth objects that could pose threats to Earth. Along the way, it picks up comets, supernovas, and other objects.
The comet comes from the Oort Cloud, a giant spherical cloud of icy comets as huge as mountains surrounding the solar system like a thick bubble. The Oort Cloud is located 186 billion miles from the sun, and its comets take an average of 200 years to travel around the sun and back.
After a year of tracking the comet's movements, astronomers found that PanSTARRS (C/2017 S3) has a hyperbolic orbit. While the planets and asteroids go around the sun in a flat plane, the green comet is unusual because it comes from above in relation to the sun. This is the first time the comet has entered the solar system.