Tony Dunn
@tony873004
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Orbit simulations of planets, comets, asteroids, spacecraft, and other interesting stuff. Amateur astronomer. BA: Physics & Astronomy, SFSU.
San Francisco
Joined April 2010
Project Lyra explores the possibility of sending a spacecraft to chase 'Oumuamua using an Earth gravity assist to reach Jupiter, which robs the craft of almost all its speed, causing it to drop to the Sun for an Oberth maneuver. Thanks @hibberdadam994 for the trajectory data!
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The James Webb Space Telescope will fire its engines and brake into its halo orbit around L2 today. #JWST
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Artemis 1 launches Monday on a 6-week round trip to the Moon. Trajectory courtesy of @NASAJPL Horizons. #Artemis @NASAArtemis.
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The trajectory for the Artemis mission has been updated by @NASAJPL Horizons following Monday's cancelled launch. #Artemis is now scheduled to launch on Saturday, Sep 3, and return on Oct. 11. @NASAJPL @NASAArtemis
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Impact! When 2022 EB5 struck the Earth north of Iceland this morning, it became the 5th asteroid to be discovered prior to impacting Earth.
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Every 26,000 years, Polaris, Alderamin, Vega, and Thuban take turns being the North Star. Original GIF: Higher-res. More years. Less jumpy. Surprise ending.
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Earth has a 2nd moon. Newly-discovered asteroid 2024 JV8 has likely been orbiting the Earth for a few years, and will continue to do so for several more months. TY to @AdrienCoffinet for noticing this object's unique path. GIF:
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Newly-discovered #asteroid 2023 NT1 passed about 1/4 the Moon's distance on July 13, but wasn't discovered until July 15, as it approached Earth in the daytime sky. It may be as large as 60 meters across, possibly larger than the asteroid that caused Meteor Crater in Arizona.
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The James Webb Space Telescope #JWST is only 10 days from launch. It will enter a powered halo orbit around the Earth-Sun Lagrange 2 point. @60Minutes has a story tonight.
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#India will launch Chandrayaan-3 to the Moon today. It will deploy a lander and a rover on the Moon. #Chandrayaan3Launch
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Newly-discovered asteroid ZTF0DxQ passed less than 1/4 Earth diameter yesterday, making it the closest-known flyby that didn't hit our planet. @renerpho.Simulation: Higher-res GIF:
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The #EuropaClipper mission will launch today. After Mars and Earth flybys, it will arrive at Jupiter in 2030. It will study the habitability of Europa, and possibly confirm the existence of its subsurface ocean.
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Newly-discovered #asteroid 2024 PT5 is about to undergo a "mini-moon event" when its geocentric energy becomes negative from September 29 - November 25.
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Newly-discovered #asteroid 2024 UQ impacted Earth's atmosphere off the coast of North America early yesterday morning. It was 1-2 meters wide.
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Due to Earth's precession, Polaris, Alderamin, Vega, and Thuban take turns being the North Star. Due to proper motion, even Arcturus had a turn 58,000 years ago. Simulation: higher res, more years, including Arcturus' brief reign.
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#Comet Tsuchinshan-ATLAS (C/2023 A3) is making its close approach to the Sun. If it survives, it could be a very bright naked-eye comet in mid October.
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K2-18b is an exoplanet that has water vapor, CO2, and methane in its atmosphere and possibly harbors an ocean. This leads to speculation that it may be habitable. This planet needs a nickname. It's hard to talk about it when I can't remember its name. Any suggestions?
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As the Jupiter-Saturn conjunction approaches, their moon systems are already merging in the sky. With our Moon and Pluto's 5 moons in the mix, tomorrow you'll be able to extend your fist at arm's length and cover 80% of our solar system's planetary moons.
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Newly-discovered asteroid A10sHcN approached Earth yesterday, passing only a few hundred miles above the South Pacific Ocean. This encounter shortened its orbit, ensuring that this Earth-crosser will make more frequent close approaches.
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In about 2 hours, newly-discovered #asteroid Sar2667 will impact Earth between London and Paris. It is only about 1 meter, so it will cause no damage. This is @sarneczky's 2nd discovered impactor.
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Earth may have a new minimoon. C26FED2 may have spent the last 3 years orbiting Earth after being captured through L1. This simulation is in a rotating frame which keeps L1 and L2 stationary. Read @BadAstronomer's blog on minimoons.
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Another October comet?.Recently-discovered A11bP7I may be a Sun-grazing comet poised to put on a show in late October.
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Newly-discovered #asteroid 2023 LS snuck up on us. Thought to be 2-6 meters wide, it passed almost as close to Earth as our geostationary satellites. It came from the direction of the Sun, so it was not discoverable until after its close approach on June 9.
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On Sunday morning, the OSIRIS-REx spacecraft will pass Earth and drop off a capsule containing bits of the asteroid Bennu that it collected 3 years ago. The capsule will land in Utah. #OSIRISREx will then continue on to its next target, #asteroid Apophis, arriving in 2029.
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Proper motion of the winter sky from 100,000 years ago to 100,000 years from now. GIFs before Twitter compression. Includes star names and date.
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#PeregrineMissionOne may "land" on the Moon after all. Unfortunately it will be a crash landing. Extrapolating trajectory data from JPL-Horizons shows the Earth flyby will put it on a collision course with the Moon.
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The Southern Pole star is not as simple. There is a lot more proper motion downstairs. Rather than stars sitting around waiting for the pole to point to them, the stars migrate into the path of the pole. Sirius will be the Southern Star twice in the next quarter million years.
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2 days ago, newly-discovered asteroid 2021 CZ3 passed 16400 km over the Pacific Ocean, coming closer than our geostationary satellites. It was undiscoverable prior to closest approach because it came from the direction of the Sun.
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#LucyMission launches early Saturday morning. It will visit Jupiter's Trojan asteroids. This animation holds Jupiter stationary in a rotating frame. GIF:
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2014 UN271 is a large comet, possibly as large as a dwarf planet. It is falling into our planetary region from the Oort Cloud. It will reach 10.1 AU, slightly farther than Saturn, in 2031.
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The first 4 asteroids discovered in 2025 are 2025 AA, 2025 AB, 2025 AC, and 2025 AD.
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On Christmas Eve, the #ParkerSolarProbe will make its closest pass ever to the Sun, flying at a record-breaking 191 km/s! 🌞 It will pass just 6.1 million km above the Sun's photosphere, navigating through the scorching corona. 🔥
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Recently-discovered #asteroid 2024 YR4 may make a very close approach to Earth in 8 years. It is thought to be 40-100 meters wide. Uncertainty is still high and more and more observations are needed confirm this.
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M60B7LC is a newly-discovered comet approaching with a slightly hyperbolic eccentricity. Is it interstellar? That's to be determined, but if it is, it won't be after a 2022 encounter with Jupiter captures it into our solar system.
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In the 21st century, the Solar System has traveled about 7 light days in its 162,000 light-year lap around the galaxy. GIF: Sim:
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#Asteroid 2024 BX1 was first discovered by @sarneczky at Piszkéstető Station in Hungary about 3 hours before it burned up over Germany. Shortly after, multiple observatories in Europe contributed over 180 observations of this asteroid.
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In less than an hour from now, newly-discovered #asteroid will strike the Philippines over Luzon. It is 1-2 meters wide.
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The JUICE mission from @esa returns to Earth this month for a gravitational assist from both the Moon & Earth. It's destination is Jupiter, where it will study its moons and even orbit Ganymede before crashing into it. @ESA_JUICE
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Another example of how Orion is a 3d volume of space. Flyn' to Orion Star Wars style!.Higher res GIF: Highest res simulation:
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The fun starts tomorrow morning. On its way to Jupiter, .The Juice spacecraft flies by the Moon for a gravitational assist that will line it up for an Earth gravitational assist a day later. #JUICE @ESA_JUICE
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#asteroid Apophis' close encounter with Earth is now less than 5 years away. It is the size of a football stadium and will come closer than our geostationary satellites.
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Next month, @NASA will launch the Europa Clipper mission. @EuropaClipper After Mars and Earth flybys, it will arrive at Jupiter in 2030. It will study the habitability of Europa, and confirm the existence of its subsurface ocean.
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Parallax of Sagittarius and Scorpius asterisms if Earth's orbit were 50,000x larger. Proper motion is not represented.
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Buzzing my house. Newly-discovered #asteroid 2024 LH1 passed just 2000 km above the #SanFrancisco Bay Area shortly after sunrise this morning, before making its close approach to Earth 1700 km above the Texas/Mexico border. It is the size of a baby giraffe.
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If you could circle the Sun at a distance of 400 LY, it would look something like this.
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On Monday, United Launch Alliance, an American aerospace manufacturer, will launch #PeregrineMissionOne to the Moon. After orbiting the Moon for several weeks, it will land on the Moon on February 23, 2024.
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#TESS launches today onto the 1st of 3 phasing orbits. After a Moon flyby it will settle into a 2:1 resonance ensuring it never comes close to the Moon again. It also keeps the Moon out of its field of view. These are in a rotating frame keeping the Moon's average position still.
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Newly-discovered #asteroid 2024 XA passed only 843 miles above the Pacific Ocean yesterday. This shortened its orbital period from 4 years to 1.5 years, ensuring it will make more frequent close encounters with Earth. It is 1-3 meters wide.
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On September 30, the Parker Solar Probe will reach perihelion, as it travels 0.05 AU from the Sun. It will travel through the Sun's corona at a record 176.45 km/s.
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The first 22 asteroids discovered this year. 2024 AA - 2024 AW.
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Here's an animated GIF of our new mini-moon 2020 CD3, discovered by @WierzchosKacper. Rotating frame keeps the Earth/Sun line stationary. Orbital elements courtesy of IUA MPEC.
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Newly-discovered #asteroid C0PPEV1 paid a heavy price for almost striking Earth this morning. Earth's gravity bent its trajectory, sending its aphelion out to the asteroid belt.
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Here is what parallax in the constellation Orion would look like if Earth's orbit were 200,000 times wider.
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Newly-discovered asteroid C42KPG1 is a kilometer-class object that passes from less than Earth's distance to the Sun to > double Pluto's distance. It's orbit is highly-uncertain (that's why it doesn't have a normal name yet), so additional observations will refine its orbit.
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Earth had a busy year modifying the orbits asteroids that dared pass closer than the Moon.
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A meteoroid impacts the Moon.
私の観測史上最大の月面衝突閃光を捉えることができました！2023年2月23日20時14分30.8秒に出現した月面衝突閃光を、平塚の自宅から撮影した様子です（実際の速度で再生）。なんと1秒以上も光り続ける巨大閃光でした。月は大気がないため流星や火球は見られず、クレーターができる瞬間に光ります。
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These are just JPEGs straight from the memory card. Later I will try to process the raw files. #Eclipse2024 #EclipseSolar2024
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A journey to Orion shows how it is more than just a pattern on the sky. It is a volume of space.
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No, NASA did not issue a warning as some sources have stated, but newly-discovered #asteroid 2024 ON, which may be as wide as half a kilometer, will pass about 1 million kilometers from Earth tomorrow. It will be bright enough for astrophotographers around the world to capture.
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.@JAXA_en's Smart Lander for Investigating Moon (SLIM) will enter into orbit around the Moon today. (Merry Christmas!) It is designed to demonstrate accurate lunar landing techniques by a small explorer. This animation is in a rotating frame holding the Earth-Sun line stationary.
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The asteroid belt, represented by 19 of its brightest members.
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Tomorrow, newly-discovered asteroid 2023 LZ will pass 0.83 Lunar distances from Earth. It is 10-32 meters wide.
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The average distance between asteroids in the #asteroid belt is nearly 1 million km. Next week, two asteroids, will pass less than 300 km from each other. You will need an observatory-grade astrophotography setup to see it, so enjoy my animation instead.
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Impact!.It is highly-likely that NORAD 40391, a rocket booster launched many years ago, will impact the Moon on March 4th. Come February, more observations should confirm this.
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Voyager 1 is now 21 light hours from the Sun. In less than 6 years, it will be our first spacecraft to venture more than a light day away. Here is a pannable simulation of our solar system's hyperbolic spacecraft.
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After new data from JPL Horizons as well as the latest statement from @astrobotic it's now looking likely that #peregrine will return home, impacting Earth over the Great Barrier Reef on January 18.
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Happy New Year! Here are all the asteroids that came closer than the Moon in 2022. HT to @kpheider, Nrco0e and others for creating the Wikipedia list.
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Is comet #C2017U1 a visitor from another solar system? Here's a simulation of its current nominal orbit. This simulation will run in your browser. Watch how fast it moves compared to a few other 2017 comet discoveries.
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On December 12, asteroid Leona will occult Betelgeuse as seen from southern Europe. This may yield clues about Betelgeuse's convection cells as well as provide a more accurate size and shape for Leona.
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Tonight, newly-discovered asteroid, 2024 JN16, will pass closer than our geostationary satellites. It will brighten to magnitude 13, putting it within reach of amateur astrophotographers in the Americas. It is 2-7 meters wide.
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The asteroid belt, represented by 19 of the brightest asteroids.
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In 2023, ~100 asteroids came closer to Earth than the Moon. Here are the first 10 of them, due to file size.
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Newly-discovered asteroid 2022 UQ1 passed 2750 km above Central America on Sunday morning. It is 9-30 meters wide.
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Tomorrow, newly-discovered #asteroid 2024 CF7 will drop vertically through the Earth-Moon system. It will pass about 1/4 the Moon's distance. It is 2-8 meters wide.
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A few hours ago, newly-discovered #asteroid 2022 EB5 collided with Earth near Iceland at a speed of 18.5 km/s. This asteroid was too small to cause damage.
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#Asteroid 2022 YG shows signs of being a quasi-satellite of Earth. @AdrienCoffinet pointed out this relationship now that we have a year's worth of data. It has been in quasi state since 1961 and will remain so until 2181. Kamoʻoalewa is another example of a quasi-satellite.
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#asteroid #2021PH27 (formerly v13aug1) has the shortest orbital period of any natural object in the #solarsystem. It was discovered on Friday the 13th by .@cerrotololo in Chile.
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No danger, but newly-discovered asteroid 2022 RM4 will pass less than 6 lunar distances on November 1. Possibly as wide as 740 meters, it will brighten to mag 14.3, well within reach of backyard telescopes. @unistellar .This is very close for an asteroid this size. #2022RM4
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Happy Halloween. Yesterday, #asteroid 2024 UG9 buzzed Earth just 2476 km above the Indian Ocean. 6 hours later, it passed 18279 km above the Moon. It is the size of a giant pumpkin 🎃.
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Newly-discovered #asteroid 2021 UA1 missed Antarctica by only 3000 km Sunday evening. It came from the daytime sky, so it was undiscoverable prior to closest approach.
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Newly-discovered #asteroid 2023 BU will pass 3500 km above the tip of South America on January 26. It is 3-8 meters wide.
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Will #Comet Tsuchinshan-ATLAS (C/2023 A3) be the next "Great Comet", or just another overhyped dud? We'll find out in 15 months.
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Meet newly-discovered asteroid 2023 FW13. @AdrienCoffinet noticed it is a quasi-satellite of Earth. Astronomer, Sam Deen, located precovery images which help confirm the 1:1 resonance with Earth. This is the same type of orbit as Kamoʻoalewa (2016 HO3).
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#OTD On this day in 1612, Galileo observed Neptune as it passed through the Jovian system. He thought it was a background star, and wasn't given credit for Neptune's discovery. Had he been watching on Jan 4, he would have seen Jupiter occult Neptune.
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Newly-discovered #asteroid 2022 AC4 will pass less than 1/4 lunar distance from Earth in a few hours. It may be bright enough to spot with backyard telescopes.
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#Asteroid 2023 AV passed less than 9200 km above the Atlantic Ocean near French Guiana on Thursday. It approached from the daytime sky. It is the first known asteroid of the year to pass closer than our geostationary satellites. It may be as large as 5 meters.
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On Monday night / Tuesday morning, this dim #asteroid Leona will #occult the bright star #Betelgeuse in parts of Europe and Africa, potentially blocking ALL its light for several seconds. This picture taken with eVscope by @unistellar
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A few hours ago, newly-discovered #asteroid 2023 VA passed closer than our geostationary satellites. It is 4-13 meters wide.
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This week, 5 asteroids have passed closer than the Moon. That is unusually high for June.
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Asteroid 2022 RM4 will pass less than 6 lunar distances on Tuesday. This is very close for an asteroid this size. Possibly as large as 740 meters, it is much larger than the ~50 meter asteroid that created Meteor Crater in Arizona. #2022RM4.
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