Published: 2020-07-23 09:33:00
Updated: 2020-07-23 10:30:26
Posted July 23, 2020 9:33 a.m. EDT
Updated July 23, 2020 10:30 a.m. EDT
Comet C/2020 F3 (NEOWISE) will be at its closest to Earth Thursday evening (63 million miles away), but it is fading as it leaves the inner solar system. This weekend is likely your last opportunity to see the comet. We'll next see this icy visitor in 7,158 years.
The last naked eye-visible comet was Hale–Bopp in 1997. Dubbed the "Great Comet of 1997," it was visible in the northern hemisphere from February through May that year.
Opportunities to see the comet for yourself are fading with it. NEOWISE is about a third as bright as it was a week ago. IAU Minor Planet Center projections show the comet reducing another half in brightness by the end of the weekend, putting it at the limits of visibility in that part of the sky. But the evolving comet continues to dazzle.
|Look to the northwestern horizon|
|Thursday, July 23||appears 24° above the horizon at 9:49 PM
sets at 12:43 AM
|Friday, July 24||
appears 26° above the horizon at 9:48 PM
|Saturday, July 25||appears 27° above the horizon at 9:47 PM
sets at 12:45 AM
|Sunday, July 26||appears 28° above the horizon at 9:46 PM
sets at 12:45 AM
Times are for central North Carolina. They begin when the Sun is sufficiently below the horizon to make out the comet and end as the comet sets about three hours later. Visit http://neowise.whatsupin.space for predictions of when the comet will be visible from other areas.
As the comet moves further from the Sun, it ejects dust and gas less vigorously. The coma, or nebulous envelope surrounding the ~3 mile-wide body of the comet, shifts to a beautiful turquoise color.
A blue colored tail formed last week. Made up of electrons stripped from the the coma, this ion tail follows the magnet lines of the solar wind.
The yellow tail made up of dust and gas ejected from the coma curves away along its orbital path
Comets are big dirty ice balls, made up of frozen water and carbon dioxide.
You can create a comet at home using the same materials including dirt (represents the dust, minerals and water found in comets, a bit of starch to hold your model together; vinegar for amino acids in a comet and rubbing alcohol for the methanol found in comets and lots of frozen carbon dioxide (dry ice) available in a small cooler near the customer service desk of most major grocery stores. Be sure to wear thick gloves and work in a well-ventilated space.
Mix everything up and heat it with a hair dryer (the Sun), and murky white clouds will jet out of your dirty icy ball. NASA's Jet Propulsion Laboratory has complete instructions and educational activites to go along with the project.