Green Comet Makes Closest Approach to Earth

File photo: A comet tears through the sky. C/2017 S3 was visible through binoculars in July. Getty Images

A green-glowing comet called C/2017 S3 will make its closest approach to Earth on Tuesday, Sky & Telescope reports.

The traveling hunk of ice and rock, which Live Science compares to a flying Incredible Hulk, has probably never traveled into the inner solar system before, the publication reported.

The comet was visible as a green-glowing dot for a time through binoculars back in July, Sky & Telescope reported. "The coma or 'atmosphere' of this comet contains certain carbon-bearing and nitrogen-bearing molecules that emit blue-green light when excited by the Sun, so that's why it has such an interesting color," NASA Near-Earth Object Observations Program Manager Kelly Fast told Newsweek.

Unfortunately, the comet is too close to the sun to be visible, Live Science reported. If you want to track its progress through space, has made a set of handy charts. "Eventually, it will get far enough away from the Sun along its orbit so that it can be seen from Earth again, but it will be far away and faint and may only be observable with large telescopes," Fast said.

Astronomers spotted the comet with the Pan-STARRS 1 telescope on September 23, 2017,'s comet catalog reported. The Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) observatory is located in Haleakala, Hawaii. The observatory watches the skies for moving objects.

The comet will make its closest approach to the Sun August 15, Sky & Telescope reported. It will travel just 0.2 astronomical units from our solar system's glowing furnace—that's about 18.5 million miles.

That might seem pretty far, but it's much closer than even Mercury. Mercury—the nearest planet to the Sun—travels as close as 29 million miles from our host star.

Later in August, NASA's Parker Solar Probe is set to travel even closer to our solar system's burning heart. The craft will "touch" the Sun, flying within just four million miles of the star. A high-tech heat shield will protect the probe from temperatures of around 2,500 degrees Fahrenheit.

Layers of superheated carbon-carbon composite surround the heat shield's 4.5-inch-thick carbon foam core, NASA reported. A special white coating will help to reflect energy from the Sun away from the probe itself.

Scientists hope the revolutionary probe will reveal some of the secrets of the Sun's turbulent corona—one of the outer layers of our star's atmosphere. This incredibly hot region is bizarrely hotter than the surface of the Sun—just one of the mysteries scientists hope the probe will be able to shed light on. The mission will also investigate space weather, like the solar wind that interacts with Earth's own magnetic field.

Don't worry if you missed out on viewing the glowing green comet, as there's still plenty to enjoy this month. Fast recommends facing south soon after darkness falls to feast upon the "smorgasbord of planets". "From right to left (west to east) you will see Venus, Jupiter, Saturn, and Mars," she said. "As for comets, 21/Giacobini-Zinner will be viewable most of the night in the northern hemisphere and should be bright enough to be seen in small telescopes.

"Finally, the Perseid meteor shower will peak around August 11-13, with best viewing after midnight, and one only needs to look up!"

This article has been updated to include comment from Kelly Fast.