Asteroid Zooms Precariously Close to Earth

Graphic showing the trajectories of Asteroid 2023 BU and the orbit of common satellites around Earth.

By Jonathan Amos

Now it’s over, we can say it: a biggish asteroid passed by Earth a short while ago.

About the size of a minibus, the space rock, known as 2023 BU, whipped over the southern tip of South America just before 00:30am GMT.

With a closest approach of 3,600km (2,200 miles), it counts as a close shave.

And it illustrates how there are still asteroids of significant size lurking near Earth that remain to be detected.

This one was only picked up last weekend by amateur astronomer Gennadiy Borisov, who operates from Nauchnyi in Crimea, the peninsula that Russia seized from Ukraine in 2014.

Follow-up observations have refined what we know about 2023 BU’s size and, crucially, its orbit.

That’s how astronomers could be so confident it would miss the planet, even though it came inside the arc occupied by the world’s telecommunications satellites, which sit 36,000km (22,000 miles) above us.

The chances of hitting a satellite are very, very small.

The time of lowest altitude was accurately calculated to be 19:27 EST on Thursday, or 00:27 GMT on Friday.

Image caption,Artwork: We still have a lot to learn about the near-Earth environment

Even if 2023 BU had been on a direct collision course, it would have struggled to do much damage.

With an estimated size of 3.5m to 8.5m across (11.5ft to 28ft), the rock would likely have disintegrated high in the atmosphere. It would have produced a spectacular fireball, however.

For comparison, the famous Chelyabinsk meteor that entered Earth’s atmosphere over southern Russia in 2013 was an object near 20m (66ft) across. It produced a shockwave that shattered windows on the ground.

Scientists at the US space agency Nasa say 2023 BU’s orbit around the Sun has been modified by its encounter with Earth.

Our planet’s gravity pulled on it and adjusted its path through space.

“Before encountering Earth, the asteroid’s orbit around the Sun was roughly circular, approximating Earth’s orbit, taking 359 days to complete its orbit about the Sun,” the agency said in a statement.

“After its encounter, the asteroid’s orbit will be more elongated, moving it out to about halfway between Earth’s and Mars’ orbits at its furthest point from the Sun. The asteroid will then complete one orbit every 425 days.”

There is a great effort under way to find the much larger asteroids that really could do damage if they were to strike the Earth.

Graphic: Asteroid populations

The true monsters out there, like the 12km-wide rock that wiped out the dinosaurs, have likely all been detected and are not a cause for worry. But come down in size to something that is, say, 150m across and our inventory has gaps.

Statistics indicate perhaps only about 40% of these asteroids have been seen and assessed to determine the level of threat they might pose.

Such objects would inflict devastation on the city scale if they were to impact the ground.

Prof Don Pollacco from the University of Warwick, UK, told BBC News: “There are still asteroids that cross the Earth’s orbit waiting to be discovered.

“2023 BU is a recently discovered object supposedly the size of a small bus which must have passed by the Earth thousands of times before. This time it passes by only 2,200 miles from the Earth – just 1% of the distance to the moon – a celestial near miss.

“Depending on what 2023 BU is composed of it is unlikely to ever reach the Earth’s surface but instead burn up in the atmosphere as a brilliant fireball – brighter than a full moon.

“However, there are likely many asteroids out there that remain undiscovered that could penetrate the atmosphere and hit the surface to cause significant damage – indeed many scientists think we could be due such an event.”

HAARP Project Bounces Waves Off Asteroid

A 500-foot asteroid passing just twice the distance from Earth to the moon was recently the target of radio signals emitted by a powerful transmitter deep within the heart of Alaska, as part of an effort to enhance our ability to detect potentially deadly space objects.

The experiment, which bounced long-wavelength radio signals off the surface of the passing object to reveal information about its interior and composition, was conducted last week at Alaska’s High-frequency Active Auroral Research Program (HAARP) research facility near Gakona.

The test, which targeted an asteroid called 2010 XC15, was part of a joint research effort with NASA to prepare for the arrival of the 1,100-foot-wide asteroid Apophis in 2029. Discovered in 2004 and originally believed to pose a potential threat to Earth in the decades ahead, it is now believed that the object’s close approach will not pose any direct threat to Earth.

Mark Haynes, a radar systems engineer at NASA’s Jet Propulsion Laboratory (JPL) and the project’s lead investigator said that last week’s experiment marked the first time an asteroid was monitored in such a way, and at such low frequencies.

The data that was collected will be analyzed in the weeks ahead, with findings from the research effort published later this year.

Haynes added that the experiment “shows the value of HAARP as a potential future research tool for the study of near-Earth objects.”

HAARP Facility

(Credit: UOA/HAARP)

Although several similar efforts involving planetary defense against asteroid impacts are currently underway, the long wavelength radio signals that HAARP employs can also provide information about the interior of such objects, not just their exterior shape and size.

Understanding the composition of asteroids and other details about their makeup and interior could potentially provide crucial data in future efforts toward defending against such an object, should one ever pose a direct threat to our planet.

According to NASA, each year at least one car-sized asteroid will collide with Earth’s atmosphere, burning up before ever striking the surface and producing a vivid fireball as it streaks through the sky during reentry.

However, larger asteroids approaching the size of a modern football field also strike the Earth every couple of thousand years. Fortunately, objects large enough to cause widespread cataclysmic damage to our planet only cross paths with us every few million years.

Still, preparing for such eventualities had been the driving force behind the successful first test of NASA’s Double Asteroid Redirection Test mission, or DART, on September 26, 2022.

Also earlier this year, tests similar to those conducted at the HAARP facility last week succeeded in bouncing long-wavelength radio signals off the surface of the Moon, whose size, distance, and predictable orbital path around the Earth makes it a much easier target than distant asteroids passing near our planet.

Following Tuesday’s experiment, more than 300 reception reports from citizen scientists tracking the effort were logged, according to HAARP program manager Jessica Matthews, who said in a press release that data has been provided “from the amateur radio and radio astronomy communities from six continents who confirmed the HAARP transmission.”

A joint program of the University of Alaska Fairbanks and military partners that include the U.S. Air Force, Navy, and the Defense Advanced Research Projects Agency (DARPA), HAARP was originally conceived as a program to study the thin layer of Earth’s atmosphere between 50 and 600 miles from Earth known as its ionosphere for its potential use in surveillance and radio communications.

Long a target of unfounded conspiracy theories, the HAARP facility has been operated by the University of Alaska at Fairbanks since 2015.

Carl Sagan’s Take on Astrology

Astrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that claim to discern information about human affairs and terrestrial events by studying the apparent positions of celestial objects. Different cultures have employed forms of astrology since at least the 2nd millennium BCE, these practices having originated in calendrical systems used to predict seasonal shifts and to interpret celestial cycles as signs of divine communication.

The scientific community rejects astrology as having no explanatory power for describing the universe, and considers it a pseudoscience.  Scientific testing of astrology has been conducted, and no evidence has been found to support any of the premises or purported effects outlined in astrological traditions. There is no proposed mechanism of action by which the positions and motions of stars and planets could affect people and events on Earth that does not contradict basic and well understood aspects of biology and physics. Those who have faith in astrology have been characterised by scientists including Bart J. Bok as doing so “…in spite of the fact that there is no verified scientific basis for their beliefs, and indeed that there is strong evidence to the contrary”.

The Biggest Satellites that have fallen to Earth 


Name: Skylab
Reentry Date: July 11, 1979
Reentry Location: South Western Australia
Size: 79 metric tons
Type: Uncontrolled reentry

The American space station’s reentry was celebrated by media in the United States, with two competing San Francisco newspapers even offering rewards for parts or damaged property.

Salyut 7

Name: Salyut 7/Kosmos 1686
Reentry Date: February 7, 1991
Reentry Location: Capitán Bermúdez, Argentina
Size: 40 metric tons
Type: Large, uncontrolled reentry

The Soviet space station had been uninhabited for almost 5 years when it returned to Earth, along with the unmanned spacecraft Kosmos 1686, showering a small Argentinian town with debris.


Name: Mir
Reentry Date: March 23, 2001
Reentry Location: South Pacific Ocean
Size: 120 metric tons
Type: Large, controlled destructive reentry

Mir, despite efforts to save the 15-year-old Russian space station for commercial purposes, reentered the atmosphere over Fiji, and fragments fell into the South Pacific.

Saturn S-II-13

Name:Saturn S-II-13 (Saturn V Stage)
Reentry Date:  January 11, 1975
Reentry Location: Atlantic
Size: 49 metric tons
Type: Uncontrolled reentry

The S-II was the second stage used on the massive Saturn V rocket, famous for launching Apollo astronauts to the moon. The S-II was used for the 13 launches of the Saturn V, including the 49 metric ton stage that reentered on January 11, 1975.

Cosmos 1402

Name: Cosmos 1402 (nuclear spy satellite)
Reentry Date: January 23, 1983
Reentry Location: Indian Ocean
Size: 4 metric tons
Type: Uncontrolled reentry

Satellite nuclear reactors were normally jettisoned to a safe “parking orbit” when the satellites reentered, but Cosmos 1402’s reactor remained attached until breaking up over the Indian Ocean. Here, an American orbital analyst monitors the satellites trajectory from NORAD.

Mars 96

Name:Mars 96 (Mars probe)
Reentry Date: November 17, 1996
Reentry Location: Bolivia, Chile, Pacific Ocean
Size: 7 metric tons
Type: Uncontrolled reentry

Mars 96 was a Russian satellite meant to send four probes to Mars, but failed and returned to Earth crashing into an unknown location in Bolivia, Chile, or the Pacific. No parts of the spacecraft, including its 200 grams of plutonium-238 fuel, have been found.

Space Shuttle Columbia

Name:Columbia (STS-107)
Reentry Date: February 1, 2003
Reentry Location: Texas, Louisiana
Size: 106 metric tons
Type: Large, controlled, destructive reentry

During the reentry of STS-107, damage to the shuttle’s left wing shielding during launch allowed hot gases to enter the wing structure of the shuttle, leading to the disintegration of the vehicle. All seven crew members were killed, and debris was scattered over northern Texas and eastern Louisiana.

Big Blast Off at Kennedy Space Center

The Space Launch System (abbreviated as SLS) is an American super heavy-lift expendable launch vehicle developed by NASA starting in 2011. The first launch, designated Artemis 1, occurred on November 16, 2022 from Kennedy Space Center. It replaces the Ares I and Ares V launch vehicles, which were cancelled along with the rest of the Constellation program, a previous program aimed to return to the Moon. The SLS is the successor to the retired Space Shuttle, and the primary launch vehicle of NASA’s deep space exploration plans through the 2020s. The SLS has the highest payload capacity of any currently operational launch vehicle and the second-highest capacity of any rocket ever to reach orbit, trailing the Saturn V. Crewed lunar flights are planned as part of the Artemis program, leading to a possible human mission to Mars. The SLS is being developed in three major phases with increasing capabilities: Block 1, Block 1B, and Block 2. As of August 2019, SLS Block 1 launch vehicles are to launch the first three Artemis missions and[29] five subsequent SLS flights are planned to use Block 1B, after which all flights will use Block 2.

Mysterious X-37B spaceplane returns to Earth after staggering long mission

The U.S. military’s mysterious X-37B has returned to Earth following a record-setting 908 days in orbit around the planet, though what it was doing for all that time largely remains a closely guarded secret. The curious unmanned craft reportedly touched down at NASA’s Kennedy Space Center early Friday morning and was preceded by a pair of powerful sonic booms that rattled residents, who were left scratching their heads until the source of the sounds was ultimately revealed. The landing marked the conclusion of the X-37B’s sixth mission, which began when it was launched back in May of 2020.

While details surrounding the X-37B mission are somewhat scant, a U.S. Space Force press release touting the craft’s return gave some insight into some of the work that had been conducted during the 908 days it was orbiting the Earth. They revealed that one experiment aboard the space plane “successfully harnessed solar rays outside of Earth’s atmosphere and aimed to transmit power to the ground in the form of radio frequency microwave energy.” Meanwhile, a NASA study utilizing the craft’s marathon mission length looked at “the effect of long-duration space exposure on seeds.” The space plane’s 908 days in orbit smashed the record previously set by the X-37B fifth mission, which lasted 780 days.

Space Force Uniforms are Definitely Unique

The United States Space Force (USSF) is the space service branch of the U.S. Armed Forces, one of the eight U.S. uniformed services, and the world’s only independent space force. Along with its sister branch, the U.S. Air Force, the Space Force is part of the Department of the Air Force, one of the three civilian-led military departments within the Department of Defense. The Space Force, through the Department of the Air Force, is overseen by the secretary of the Air Force, a civilian political appointee who reports to the secretary of defense, and is appointed by the president with Senate confirmation. The military head of the Space Force is the chief of space operations who is typically the most senior Space Force officer. The chief of space operations exercises supervision over the Space Force’s units and serves as one of the Joint Chiefs of Staff.

Space Force personnel are called Guardians.

This uniform description from Reddit: The new Space Force uniforms make you look like a fascist bus-driver from “The Jetsons.”

SpaceX launches another 52 Starlink satellites, lands rocket at sea

SpaceX launched another 52 of its Starlink internet satellites to orbit Saturday evening (Sept. 24) and also aced a rocket landing at sea.

A Falcon 9 rocket topped with 52 Starlink spacecraft lifted off from Florida’s Cape Canaveral Space Force Station Saturday at 7:32 p.m. EDT (2332 GMT).

Just under nine minutes later, the Falcon 9’s first stage came back to Earth for a pinpoint touchdown on the SpaceX “droneship” A Shortfall of Gravitas, which was stationed in the Atlantic Ocean. It was the fourth liftoff and landing for this particular booster, according to a SpaceX mission description.

Starlink is a satellite internet constellation operated by SpaceX, providing satellite Internet access coverage to 40 countries. It also aims for global mobile phone service after 2023. SpaceX started launching Starlink satellites in 2019. As of September 2022, Starlink consists of over 3,000 mass-produced small satellites in low Earth orbit (LEO), which communicate with designated ground transceivers. Starlink provides internet access to over 500,000 subscribers as of June 2022.

The SpaceX satellite development facility in Redmond, Washington houses the Starlink research, development, manufacturing, and orbit control teams. The cost of the decade-long project to design, build, and deploy the constellation was estimated by SpaceX in May 2018 to be at least US$10 billion. In February 2017, documents indicated that SpaceX expects more than $30 billion in revenue by 2025 from its satellite constellation, while revenues from its launch business were expected to reach $5 billion in the same year.

60 Starlink satellites stacked together before deployment on 24 May 2019