Posted by Eddie Irizarry and Deborah Byrd in SPACE | March 4, 2021

You can watch online as the notorious near-Earth asteroid Apophis brushes past Earth on March 5-6, 2021. This flyby is a precursor to the tantalizingly close sweep Apophis will make in 2029.

The Virtual Telescope Project, based in Rome, Italy, captured asteroid (99942) Apophis on March 2, 2021. The asteroid shows as a dot – while the stars around it show as streaks – because the telescope was tracking the asteroid’s motion. It is moving through space with respect to Earth at 4.658 km/sec (2.894 miles/sec). Image via Virtual Telescope.

Watch online as infamous asteroid Apophis makes a close flyby of Earth on March 5-6, 2021. No, it won’t strike Earth at this flyby (when closest, it’ll be about 44 times the moon’s distance), but the asteroid is now within range of earthly telescopes and radar. Astronomers are tracking its movements, and you can get a peek. Apophis is a near-Earth asteroid with a relatively large size (nearly 400 meters, or yards, across). It gained notoriety in 2004 when early observations suggested it might strike Earth in 2029. Though it will come breathtakingly close to Earth in 2029, a strike that year was subsequently ruled out. Apophis is not expected to strike Earth in this century.

The Virtual Telescope Project in Rome is offering a free online viewing session for asteroid Apophis on March 5-6, 2021. The feed will start on March 6 at 00:00 UTC (March 5 at 7 p.m. EST; translate UTC to your time).

Click here to go to Virtual Telescope’s site.

Look below for more information of Apophis’ very close pass in 2029

Asteroid Apophis will sweep closest to our planet on March 6, 2021, at 01:15 UTC (on March 5 at 8:15 p.m. EST). At this 2021 pass, it’ll come within 10,471,577 miles (16,852,369 km).1.2M508Must Watch Sky Events in 2021

NASA’s Goldstone Deep Space Communications Complex in California has had the asteroid on its observing schedule since March 3, 2021, and plans to continue watching it through March 14. Researchers at the Green Bank Telescope in West Virginia also began observing Apophis on March 3; Green Bank is coordinating observations with Goldstone because the use of these two telescopes together allows the data to be sharper. Astronomers are, of course, mourning the loss of the Arecibo telescope in Puerto Rico. Word on the street is that Arecibo – known for its radar observations of asteroids – would have been the world’s best telescope for observing Apophis this year. Arecibo suffered a collapse last fall, however, which caused the telescope to be decommissioned. The International Asteroid Warning Network (IAWN) – which has members in Europe, Asia, and South and North America – is serving as a clearinghouse for the 2021 campaign to observe Apophis. Its coordinator is astronomer Vishnu Reddy, a planetary defense expert at the University of Arizona.

Click here for more information about Virtual Telescope’s live viewing of asteroid Apophis on March 5-6, 2021.

Earlier observations with Goldstone and Arecibo radar observations confirmed that Apophis is elongated in shape. Image via NASA/ JPL.

In addition, astronomers are planning to study asteroid Apophis using NASA’s NEOWISE infrared space telescope in April 2021. This is the same telescope that discovered 2020’s favorite comet, Comet NEOWISE, which has now faded from view.

After the 2029 pass, asteroid Apophis will also make noteworthy passes near Earth in 2036 and again in 2068. Earth strikes in 2029 and 2036 have been ruled out. As of February 2021, the chances of impact during the 2068 flyby of Apophis are now 1 in 380,000. That’s a 99.99974% chance the asteroid will miss the Earth in 2068.

The 2021 observations of Apophis should further improve our knowledge of the asteroid’s shape and spin, and they’ll help reduce uncertainties in the space rock’s orbit caused by what’s called the Yarkovsky acceleration.

In some instances, acceleration – a change in an object’s speed and direction through space – can help avoid a collision. Studies of Yarkovsky acceleration as related to asteroid Apophis suggest this is the case for this asteroid. Previous calculations (made in 2016) had all but ruled out the probability of an impact in 2068. The chance of an impact was seen in 2016 as vanishingly small, at just 1 in 150,000 odds of impact, or a 99.99933% chance the asteroid would miss the Earth.

The more recent observations, first discussed in October 2020 and updated again in early 2021, show a decreasing risk.

It’s a Yarkovsky acceleration of asteroid Apophis – detected by astronomers at the University of Hawaii – that has reduced the impact probability for the 2068 flyby.

Orbit of asteroid Apophis (pink) in contrast to the orbit of Earth (blue). The yellow dot represents the sun. Apophis takes 323.6 days to orbit the sun. Earth takes 365.3 days. Thus this asteroid is a fairly frequent visitor to our region of space. Image via Phoenix7777/ Wikimedia Commons.

Astronomer Dave Tholen and collaborators used the 323-inch (8.2-meter) Subaru Telescope at Maunakea, Hawaii, to make the most recent observations. These astronomers were then able to update the Earth-impact risk from Apophis, including the latest measurements of the Yarkovski effect, which arises from a minuscule push imparted by sunlight.

Visit the Apophis page at the Center for Near Earth Object Studies

The new work by Tholen and colleagues suggests that Apophis – whose estimated diameter is between 1,115 and 1,214 feet (340 to 370 meters) – is drifting more than 500 feet (about 170 meters) per year from its expected position in its orbit.

Tholen has been tracking the motion of Apophis in the sky since he and his colleagues discovered it from Kitt Peak National Observatory near Tucson, Arizona, in on June 19, 2004. He commented in the statement:

We have known for some time that an impact with Earth is not possible during the 2029 close approach.

The new observations we obtained with the Subaru telescope [in 2020] were good enough to reveal the Yarkovsky acceleration of Apophis, and they show that the asteroid is drifting away from a purely gravitational orbit by about 170 meters [about 500 feet] per year, which is enough to keep the 2068 impact scenario in play.

These observations aren’t easy to obtain and analyze. Factors such as the asteroid’s distance at the time of observation, its composition, its shape and its surface features all affect the outcome.

But astronomers are pushing to understand the orbit of asteroid Apophis because of its close sweeps past our planet in this century and beyond.

Read more about the Yarkovsky effect: Pushing asteroids around with sunlight

Apophis is, of course, not the only near-Earth asteroid. In recent years, astronomers have been able to find and track many tiny asteroids sweeping near Earth. For example, on September 24, 2020, asteroid 2020 SW swept even closer to us than our meteorological and television satellites as well as other geostationary satellites, which orbit our planet at some 22,300 miles (35,900 km) from Earth’s surface. Asteroid 2020 SW came within about 7% of the Earth-moon distance. But asteroid 2020 SW is estimated to be only about 14 to 32 feet (about 4.5 to 10 meters) in diameter. That’s very small in contrast to asteroid Apophis.

This animation shows the distance between the Apophis asteroid and Earth at the time of the asteroid’s closest approach in 2029. The blue dots are manmade satellites orbiting our planet, and the pink represents the International Space Station. Image via NASA/ JPL-Caltech.

The 2029 pass of asteroid Apophis. The April 13, 2029, encounter of Apophis with Earth will be extremely close. At its closest in 2029, Apophis will sweep just 23,441 miles (37,725 km) from our planet, or about 10% of the Earth-moon distance. That’s very close for a space rock over 1,115 ft (340 meters) across! Lance Benner of NASA/JPL commented:

This will be the closest approach by something this large currently known. (In 2029) Apophis will be visible to the unaided eye for several hours, and Earth tides will probably change its spin state.

Friday, April 13, 2029, will be a showtime for asteroid Apophis, for the general public and astronomers alike. Apophis will come so close that it’ll be visible to the unaided eye alone; something that almost never happens with asteroids. According to NASA, Apophis will first become visible in the Southern Hemisphere and will look like a speck of light moving across Australia during this close encounter. It will be over the Atlantic Ocean at its closest approach to Earth. It will move so fast that it crosses the Atlantic in just an hour, and will have crossed the U.S. in the late afternoon/early evening within the next hour. Calculations indicate that Apophis will reach a visual magnitude of 3.1 during this approach, comparable to the stars in the Little Dipper. In 2029, Apophis is expected to be visible to the unaided eye from some areas of Australia, western Asia, Africa, and Europe.

Like many other asteroids, Apophis has been classified as a potentially hazardous asteroid by the International Astronomical Union’s Minor Planet Center. That just means it’s an asteroid whose orbit brings it close to Earth on occasion, which is large enough to cause “significant regional damage” in the event of an impact. A survey by the NEOWISE spacecraft in 2012 suggested that there are 4,700 ± 1,500 potentially hazardous asteroids with a diameter greater than 100 meters.

According to some estimates, an asteroid the size of Apophis can be expected to strike Earth about every 80,000 years.Diagram of Earth with moon's orbit and a line coming very close to Earth, slightly bent as it passes.

As a result of the extremely close approach of April 2029, it is expected that perturbations caused by Earth’s gravity will change Apophis’ orbit from the Aten to the Apollo class. Image via NASA/ JPL.

Bottom line: Asteroid Apophis will sweep past Earth on March 5-6, 2021, its closest pass before it buzzes by in 2029. The large asteroid is noteworthy for its extremely close approaches to Earth in 2029, 2036 and 2068. Observations show any impact this century is unlikely.

Read more about the Yarkovsky effect: Pushing asteroids around with sunlight

Large asteroid Apophis will safely fly by Earth on Friday

By Elizabeth Howell a day ago

An animation shows Apophis' 2029 path compared to the swarm of satellites orbiting Earth. The asteroid won't pass nearly as closely in 2021; it will remain 44 times more distant than the moon.

An animation shows Apophis’ 2029 path compared to the swarm of satellites orbiting Earth. The asteroid won’t pass nearly as closely in 2021; it will remain 44 times more distant than the moon. (Image credit: NASA/JPL-Caltech)

Our solar system’s most infamous asteroid will pass by Earth on Friday (March 5), and with a high-end telescope you can watch it as it safely whizzes by our planet.

We’re talking about none other than asteroid 99942 Apophis, which will come even closer to Earth on April 13, 2029, when it passes through the zone of high-altitude satellites. But even then, Apophis won’t hit Earth as some had predicted — so instead, let’s focus on what science is coming from these flybys.

The near-Earth asteroid is roughly 1,000 feet (300 meters) across and was discovered in 2004. Initial early estimates suggested there was a small chance of Apophis hitting Earth in 2029, but scientists ruled out that possibility after looking at archival images, NASA said

Related: Scientists prepare for their last good look at asteroid Apophis before 2029 flybyClick here for more videos…CLOSE 0% PLAY SOUND

Even though the planet is not in danger, however, scientists will still appreciate the rare flybys in 20210 and 2029 to look at the shape of the asteroid — and perhaps even surface features in 2029 — in our ongoing study to learn more about asteroids, which have been around since early in the solar system’s history (our neighborhood came together roughly 4.5 billion years ago).

Apophis’ closest approach Friday will be at 0.11 astronomical units (an astronomical unit is the average distance between the Earth and the sun, or roughly 93 million miles or 150 million kilometers). While the flyby is close in astronomical terms, Apophis will remain at a distance of 44 times the distance between the Earth and the moon.

Personal telescopes may struggle to see Apophis due to its faintness, as it’s only going to have a visual magnitude of roughly 15 or 16, according to EarthSky. You’ll either need a 12-inch diameter or larger telescope to spot it visually, or to equip a slightly smaller telescope with a sensitive camera to process the images for later viewing.

Your best chance to see it may be early on Saturday (May 6), when Unistellar Optics coordinates a citizen-science campaign to observe Apophis around the time it gets closest to Earth. From the perspective of viewers in parts of the U.S., between roughly 12:55 a.m. EST and 1:04 a.m. EST (0555 GMT and 0604 GMT), Apophis will pass in front of a star. The broad sweep of terrain where the event will be visible extends through Montana, Wyoming, Colorado, Kansas, Oklahoma, Texas, Arkansas and Louisiana, and perhaps some bordering areas as well. A map and more details on calibrating a Unistellar eVscope are available in a company blog post.

Scientists love to use these close flybys to scan space rocks with radar to learn more about the asteroids’ shape and rotation. Unfortunately, Earth’s most powerful radar system is permanently offline, since the Arecibo Observatory radio telescope in Puerto Rico collapsed in December and is being dismantled.

The interim replacement is NASA’s Goldstone Deep Space Communications Complex in California, which was scheduled to begin observations of the asteroid Wednesday (March 3) and continue through March 14. The space-based asteroid-hunting NEOWISE mission may also be able to spot the asteroid later in April, principal investigator Amy Mainzer told 

“I’m hoping we can get some details of the surface roughness, the thickness of any rocks and dust on the surface of the object,” Mainzer said earlier this month, adding that the data would come from combining NEOWISE observations gathered in December 2020 and April 2021. “It may help us learn quite a bit more about it, if we’re very lucky,” she added.

While Apophis is not an imminent threat to Earth, scientists are running a planetary defense scenario pretending that they just spotted it in the sky in December, to prepare for a possible situation in the future. But you can rest easy, as there are no imminent threats known to Earth at this time — and NASA and its partners continue to scan the sky and practice disaster management, just in case.

Follow Elizabeth Howell on Twitter @howellspace. Follow us on Twitter @Spacedotcom and on Facebook. 

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After suggesting that we should nuke Mars to terraform it, SpaceX CEO Elon Musk took to Twitter yesterday to warn us all that “a big rock will hit Earth eventually and we currently have no defense.”

The ominous warning came in reply to podcast personality Joe Rogan, who shared an article by The Daily Express, a British tabloid newspaper, about asteroid Apophis, warning of an imminent “asteroid shock” — a sensationalist spin of a harmless cosmic event.

Apophis is a 370-meter in diameter near-Earth asteroid, first spotted in 2004, that could hit the Earth in 2029 — but only with a probability of well under three percent. It is nonetheless categorized as a “Potentially Hazardous Asteroid” by NASA and considered an unlikely but worrisome space hazard.

NASA had discussed the asteroid at this year’s 2019 Planetary Defense Conference back in April, noting that Apophis will “cruise harmlessly by Earth, about 19,000 miles (31,000 kilometers) above the surface,” according to a blog post by NASA’s Jet Propulsion Laboratory (JPL).


In fact, it’ll pass so close, that its gravity could affect Earth.

“It is possible that there will be some surface changes, like small avalanches,” Davide Farnocchia, an astronomer at JPL’s Center for Near Earth Objects Studies, said in the blog post.

While the Express article mentioned that “NASA is preparing for ‘colossal God of Chaos’ rock” — a headline that could easily be read as NASA preparing for the worst “Armageddon”-style by unsuspecting tabloid readers, the reality is substantially different. Scientists at JPL had discussed sending a small spacecraft to meet Apophis as it sails by.

“The Apophis close approach in 2029 will be an incredible opportunity for science,” said Marina Brozovi, a JPL radar scientist, in a statement in April. “We’ll observe the asteroid with both optical and radar telescopes. With radar observations, we might be able to see surface details that are only a few meters in size.”


That doesn’t mean Musk is wrong, though. His comments come, for instance, after a “city killer” asteroid of immense proportions whizzed past Earth almost completely undetected by astronomers last month.

Still, we’re not quite as defenseless as Musk suggested. One of NASA’s upcoming missions, for example, is planning to smash a probe into a distant asteroid at 13,500 mph to deflect it away from Earth.

The team behind the mission dubbed “Double Asteroid Redirection Test” — the first ever mission to come out of NASA’s Planetary Defense Coordination Office — revealed parts of its new spacecraft in July, a column of honeycomb structured aluminum that will later be outfitted with massive solar arrays.

The plan is to launch the spacecraft aboard a SpaceX Falcon 9 rocket — ironic, considering Musk’s stance on the subject — from the Vandenberg Air Force Base in California in 2021.

Article Editor’s note 8/19: An earlier version of this story incorrectly claimed that the asteroid Apophis could come closer to Earth than the International Space Station. It has been updated.

READ MORE: Today, Elon Musk is worried about asteroids 

More on asteroids: “City Killer” Asteroid Whizzes Past Earth Almost Undetected