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Comet NEOWISE: 10 big questions (and answers) about the icy wanderer – Space.com
See Comet NEOWISE?
(Image credit: NASA/Johns Hopkins APL/Naval Research Lab/Parker Solar Probe/Brendan Gallagher)
If you spot Comet NEOWISE, let us know! Send images and comments to spacephotos@space.com to share your views.
Comet NEOWISE has is delighting skywatchers around the Northern Hemisphere. But what makes this comet so special?
The comet made its closest approach to the sun on July 3 but, until now, was only visible in the sky before dawn. Now, for keen observers in the Northern Hemisphere, the comet has been getting higher in the evening sky, sparkling northwest below the Big Dipper constellation, according to Joe Masiero, deputy principal investigator of NEOWISE (NASA’s Near-Earth Object Wide-field Infrared Survey Explorer, the NASA space telescope that first spotted the comet).
One of the most fascinating details about Comet NEOWISE is that it won’t return to our skies for another 6,800 years. But that’s not the only thing that makes this icy space rock special. So let’s take a dive into what makes Comet NEOWISE unique — and a little weird.
Related: How to see Comet NEOWISE in the evening sky now
What is Comet NEOWISE?
Officially known as C/2020 F3, Comet NEOWISE is a comet that was discovered on March 27, 2020, by NEOWISE, the asteroid-hunting afterlife of the Wide-field Infrared Survey Explorer (WISE) mission.
Comets, often nicknamed “cosmic snowballs,” are icy, rocky objects made up of ice, rock and dust. These objects orbit the sun, and as they slip closer to the sun most comets heat up and start streaming two tails, one made of dust and gas and an “ion tail” made of electrically-charged gas molecules, or ions.
Can I see it?
Yes! Because it is especially bright, the comet is visible in the night sky with the naked eye. Skywatchers in the Northern Hemisphere can spot the object just after sunset, to the northwest just under the Big Dipper constellation.
In fact, the comet is so bright that scientists are “able to get a lot more and better data than we typically do for most comets,” Kramer said. “We’re able to study it with a wide variety of different telescopes, and that’ll allow us to do really interesting studies.”
Related: How to photograph Comet NEOWISE: NASA tips for stargazers
Do I need a telescope?
No! Because Comet NEOWISE is an especially bright object, it is relatively easy for astronomy enthusiasts to spot it in the night sky with just the naked eye, although binoculars or a small telescope will give you a better view.
“The fact that we can see it is really what makes it unique,” Kramer said. “It’s quite rare for a comet to be bright enough that we can see it with a naked eye or even with just binoculars.”
More: Best telescopes for the money — 2020 reviews and guide
What does it look like in the sky?
To those spotting the comet with the naked eye, without any tools or instruments like a telescope, it looks like a fuzzy star with a little bit of a tail. You do need to be away from city lights, though.
With binoculars or a small telescope, the comet will be more clear and the tail will be easier to spot.
Related: Amazing photos of Comet NEOWISE from the Earth and space
How much water is in the comet?
There is “about 13 million Olympic swimming pools of water,” in Comet NEOWISE, Emily Kramer, a science team co-investigator forNASA’s NEOWISE at NASA’s Jet Propulsion Laboratory, said during a news conference July 15. “So that’s a lot of water.”
“Most comets are about half water and half dust,” she added.
Does it have a tail?
Comet NEOWISE has two tails that typically accompany every comet.
As a comet nears the sun, it warms up and material pulls away from the surface into a tail. Often, dust is pulled away along with gases from sublimating (going directly from solid to a gas) ice. This dust tail is the sweeping trail seen in most comet images. Comets also have an ion tail made up of ionized gas blown back by the solar wind.
Researchers studying Comet NEOWISE might actually also have a sodium tail. By observing what they believe to be atomic sodium in the comet’s tail, researchers can glean keen insight into the object’s makeup.
How big is Comet NEOWISE?
Comet NEOWISE is about 3 miles (5 kilometers) in diameter, “which is a reasonably large but roughly average-size comet,” Kramer said.
“It’s rare to see something that’s this bright,” she added. “There are comets that are of this size that we see regularly, but most of them are so from Earth that they don’t get this bright. They’re too far from the sun and the Earth to be able to see them in the way that we’re seeing this Comet NEOWISE.”
How fast is Comet NEOWISE?
The comet is traveling at about 40 miles per second (that’s about 144,000 mph, or 231,000 km/h).
Joe Masiero, deputy principal investigator of the NEOWISE mission, said the the comet is moving about twice as fast as the Earth’s speed around the sun. But don’t expect that rapid clip to last.
Because of the comet’s extremely elliptical orbit, it will slow down as it reaches its farthest point from the sun, then fall back toward the inner solar system and accelerate again when it heads back round the sun. That trip around the sun is over for Comet NEOWISE’s current orbit and it’s moving back to the outer solar system.
“And so as it goes farther from the sun, [it] will be slowing down as it climbs back up that gravity well,” Masiero said.
Will it hit Earth?
Have no fear, Comet NEOWISE will not hit Earth.
“This particular comet has no possibility of impacting the Earth. It crosses the plane of Earth orbit well inside of recovery orbit and almost near the orbit of Mercury, so there’s absolutely no hazard from this comet,” Lindley Johnson, the planetary defense officer and program executive of NASA’s Planetary Defense Coordination Office at NASA Headquarters, said during the news conference.
The comet orbits the sun every 600 to 700 years, Johnson said. The comet is currently about 70 million miles (111 million kilometers) away from Earth.
Is it from interstellar space?
No, Comet NEOWISE originates in our own solar system. To date, only two interstellar objects have been discovered: ‘Oumuamua and Comet Borisov.
“This one we know it’s not Interstellar object. By watching its motion, we can see that it’s bound to the sun’s gravity,” Kramer said. “So it’s coming in very rapidly and then it’s going to go far back out again and then but then should come back in again in about 6,800 years.”
Email Chelsea Gohd at cgohd@space.com or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.
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The artwork and publicity materials showcasing a giant salmon that lived five million years ago were ready to go to promote a new exhibit, when the discovery of two fossilized skulls immediately changed what researchers knew about the fish.
Initial fossil discoveries of the 2.7-metre-long salmon in Oregon in the 1970s were incomplete and had led researchers to mistakenly suggest the fish had fang-like teeth.
It was dubbed the “sabre-toothed salmon” and became a kind of mascot for the Museum of Natural and Cultural History at the University of Oregon, says researcher Edward Davis.
But then came discovery of two skulls in 2014.
Davis, a member of the team that found the skulls, says it wasn’t until they got back to the lab that he realized the significance of the discovery that has led to the renaming of the fish in a new, peer-reviewed study.
“There were these two skulls staring at me with sideways teeth,” says Davis, an associate professor in the department of earth sciences at the university.
In that position, the tusk-like teeth could not have been used for biting, he says.
“That was definitely a surprising moment,” says Davis, who serves as director of the Condon Fossil Collection at the university’s Museum of Natural and Cultural History.
“I realized that all of the artwork and all of the publicity materials and bumper stickers and buttons and T-shirts we had just made two months prior, for the new exhibit, were all out of date,” he says with a laugh.
Davis is co-author of the new study in the journal PLOS One, which renames the giant fish the “spike-toothed salmon.”
It says the salmon used the tusk-like spikes for building nests to spawn, and as defence mechanisms against predators and other salmon.
The salmon lived about five million years ago at a time when Earth was transitioning from warmer to relatively cooler conditions, Davis says.
It’s hard to know exactly why the relatives of today’s sockeye went extinct, but Davis says the cooler conditions would have affected the productivity of the Pacific Ocean and the amount of rain feeding rivers that served as their spawning areas.
Another co-author, Brian Sidlauskas, says a fish the size of the spike-toothed salmon must have been targeted by predators such as killer whales or sharks.
“I like to think … it’s almost like a sledgehammer, these salmon swinging their head back and forth in order to fend off things that might want to feast on them,” he says.
Sidlauskas says analysis by the lead author of the paper, Kerin Claeson, found both male and female salmon had the “multi-functional” spike-tooth feature.
“That’s part of our reason for hypothesizing that this tooth is multi-functional … It could easily be for digging out nests,” he says.
“Think about how big the (nest) would have to be for an animal of this size, and then carving it out in what’s probably pretty shallow water; and so having an extra digging tool attached to your head could be really useful.”
Sidlauskas says the giant salmon help researchers understand the boundaries of what’s possible with the evolution of salmon, but they also capture the human imagination and a sense of wonder about what’s possible on Earth.
“I think it helps us value a little more what we do still have, or I hope that it does. That animal is no longer with us, but it is a product of the same biosphere that sustains us.”
This report by The Canadian Press was first published April 24, 2024.
Brenna Owen, The Canadian Press
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A new paper says a giant salmon that lived five million years ago in the coastal waters of the Pacific Northwest used tusk-like spikes as defense mechanisms and for building nests to spawn.
The initial fossil discoveries of the 2.7-metre-long salmon in Oregon in the 1970s were incomplete and led researchers to suggest the fish had fang-like teeth.
The now-extinct fish was dubbed the “saber-tooth salmon,” but the study published in the peer-reviewed journal PLOS One today renames it the “spike-toothed salmon” and says both males and females possessed the “multifunctional” feature.
Study co-author Edward Davis says the revelation about the tusk-like teeth came after the discovery of fossilized skulls at a site in Oregon in 2014.
Davis, an associate professor in the department of earth sciences at the University of Oregon, says he was surprised to see the skulls had “sideways teeth.”
Contrary to the belief since the 1970s, he says the teeth couldn’t have been used for any kind of biting.
“That was definitely a surprising moment,” Davis says of the fossil discovery in 2014. “I realized that all of the artwork and all of the publicity materials … we had just made two months prior, for the new exhibit, were all out of date.”
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April 23 (UPI) — SpaceX launched 23 Starlink satellites into low-Earth orbit Tuesday evening from Space Launch Complex 40 at Cape Canaveral Space Force Station in Florida.
Liftoff occurred at 6:17 EDT with a SpaceX Falcon 9 rocket sending the payload of 23 Starlink satellites into orbit.
The Falcon 9 rocket’s first-stage booster landed on an autonomous drone ship in the Atlantic Ocean after separating from the rocket’s second stage and its payload.
The entire mission was scheduled to take about an hour and 5 minutes to complete from launch to satellite deployment.
The mission was the ninth flight for the first-stage booster that previously completed five Starlink satellite-deployment missions and three other missions.
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