Day: July 15, 2020

Comet NEOWISE over Stonehenge

Posted on Posted in NASA, TweetTagged , Leave a comment

Have you ever seen a comet? Tonight — and likely the next few nights — should be a good chance. Go outside just at sunset and look to your northwest. The lower your horizon, the better. Binoculars may help, but if your sky is cloudless and dark, all you should need is your unaided eyes and patience. As the Sun sets, the sky will darken, and there will be an unusual faint streak pointing diagonally near the horizon. That is Comet NEOWISE. It is a 5-kilometer-wide evaporating dirty iceberg visiting from — and returning to — the outer Solar System. As the Earth turns, the comet will soon set, so you might want to take a picture. In the featured image, Comet C/2020 F3 (NEOWISE) was captured two mornings ago rising over Stonehenge in the UK. Discovered with the NASA satellite NEOWISE toward the end of March, Comet NEOWISE has surprised many by surviving its closest approach to the Sun, brightening dramatically, and developing impressive (blue) ion and (white) dust tails. via wordpress https://wp.me/p4wJUi-737

Comet NEOWISE Rising over the Adriatic Sea

Posted on Posted in NASA, TweetTagged , Leave a comment

This sight was worth getting out of bed early. Comet C/2020 F3 (NEOWISE) has been rising before dawn during the past week to the delight of northern sky enthusiasts awake that early. Up before sunrise, the featured photographer was able to capture in dramatic fashion one of the few comets visible to the unaided eye this century, an inner-Solar System intruder that might become known as the Great Comet of 2020. The resulting video details Comet NEOWISE from Italy rising over the Adriatic Sea. The time-lapse video combines over 240 images taken over 30 minutes. The comet is seen rising through a foreground of bright and undulating noctilucent clouds, and before a background of distant stars. Comet NEOWISE has remained unexpectedly bright, so far, with its ion and dust tails found to emanate from a nucleus spanning about five kilometers across. Fortunately, starting tonight, northern observers with a clear and dark northwestern horizon should be able to see the sun-reflecting interplanetary snowball just after sunset. via wordpress https://wp.me/p4wJUi-72P

Comet CG Creates Its Dust Tail

Posted on Posted in NASA, TweetTagged , Leave a comment

Where do comet tails come from? There are no obvious places on the nuclei of comets from which the jets that create comet tails emanate. One of the best images of emerging jets is shown in the featured picture, taken in 2015 by ESA’s robotic Rosetta spacecraft that orbited Comet 67P/Churyumov-Gerasimenko (Comet CG) from 2014 to 2016. The picture shows plumes of gas and dust escaping numerous places from Comet CG’s nucleus as it neared the Sun and heated up. The comet has two prominent lobes, the larger one spanning about 4 kilometers, and a smaller 2.5-kilometer lobe connected by a narrow neck. Analyses indicate that evaporation must be taking place well inside the comet’s surface to create the jets of dust and ice that we see emitted through the surface. Comet CG (also known as Comet 67P) loses in jets about a meter of radius during each of its 6.44-year orbits around the Sun, a rate at which will completely destroy the comet in only thousands of years. In 2016, Rosetta’s mission ended with a controlled impact onto Comet CG’s surface. via wordpress https://wp.me/p4wJUi-72n

The Tails of Comet NEOWISE

Posted on Posted in NASA, TweetTagged , Leave a comment

Comet NEOWISE (C/2020 F3) is now sweeping through northern skies. Its developing tails stretch some six degrees across this telescopic field of view, recorded from Brno, Czech Republic before daybreak on July 10. Pushed out by the pressure of sunlight itself, the comet’s broad, yellowish dust tail is easiest to see. But the image also captures a fainter, more bluish tail too, separate from the reflective comet dust. The fainter tail is an ion tail, formed as ions from the cometary coma are dragged outward by magnetic fields in the solar wind and fluoresce in the sunlight. In this sharp portrait of our new visitor from the outer Solar System, the tails of comet NEOWISE are reminiscent of the even brighter tails of Hale Bopp, the Great Comet of 1997. via wordpress https://wp.me/p4wJUi-72d

Comet NEOWISE from the ISS

Posted on Posted in NASA, TweetTagged , Leave a comment

Rounding the Sun on July 3rd and currently headed for the outer Solar System, Comet NEOWISE (C/2020 F3) has been growing brighter in the predawn skies of planet Earth. From low Earth orbit it also rises before the Sun, captured above the approaching glow along the eastern horizon in this snapshot from the International Space Station on July 5. Venus, now Earth’s morning star is the brilliant celestial beacon on the right in the field of view. Above Venus you can spot the sister stars of the more compact Pleiades cluster. Earthbound skygazers can spot this comet with the unaided eye, but should look for awesome views with binoculars. via wordpress https://wp.me/p4wJUi-723