OSIRIS-APEX, the follow-up to OSIRIS-REx, will study changes to asteroid from its rare close encounter with Earth in April 2029.
Posted by Leslie Eastman
Asteroid Apophis, named after the Egyptian god of chaos and destruction, is a near-Earth asteroid that has garnered significant attention due to its close approach to our home planet.
Discovered in 2004, Apophis is classified as a potentially hazardous object. Due to swing close enough to the planet in 2029, the gravitational influence will be enough to cause tremors.
A recent study led by Ronald-Louis Ballouz from Johns Hopkins University Applied Physics Laboratory suggests that the asteroid 99942 Apophis may experience tremors—similar to earthquakes—due to Earth’s gravitational pull during its close flyby on April 13, 2029, with simulations indicating significant surface changes.
Apophis, approximately 340 meters in size, will pass within about 32,000 kilometers of Earth, closer than many satellites in orbit.
When Apophis was discovered on June 19, 2004, by Roy Tucker, David Tholen, and Fabrizio Bernardi during the University of Hawaii Asteroid Survey (UHAS), initial calculations indicated that it could approach Earth with a risk of collision, especially during its pass in 2029. It didn’t help that it is named after the Egyptian god of darkness and chaos.
The original estimates for collision were as high as 2.7%, and Apophis achieved the highest rating ever on the ‘Torino scale’ – a method used to evaluate the threat that an asteroid poses to Earth.
However, new calculations and observations have led scientists to conclude that there will be no impact….for at least 100 years.
….Using the data available at the time, astronomers believed that there was a chance that the flyby could alter the trajectory of Apophis in a way that would line it up for a collision with Earth in 2068.
However, radar observations of Apophis made by NASA’s Goldstone Deep Space Communications Complex in California and the Green Bank Observatory, West Virginia, in March 2021 greatly improved our knowledge of the asteroid’s current orbit and allowed astronomers to finally rule out any chance of Earth impact for at least 100 years.
And while it won’t strike Earth, Apophis will be bright enough in the skies to be visible to the unaided eye. So, the viewing parties could be fun!
As I mentioned, the viewing parties of the National Aeronautics and Space Administration (NASA) are currently making their own plans for up-close-and-personal observations.
The OSIRIS-APEX mission is slated to visit the asteroid. It continues the OSIRIS-REx mission, which successfully collected and returned samples from asteroid Bennu (which I reported on in a 2023 post).
OSIRIS-APEX is a mission to study the physical changes to asteroid Apophis that will result from its rare close encounter with Earth in April 2029. That year, Apophis’ orbit will bring it within 20,000 miles (32,000 kilometers) of Earth’s surface — closer to Earth than our highest-altitude satellites. Our planet’s gravitational pull is expected to alter the asteroid’s orbit, change how fast it spins on its axis, and possibly cause quakes or landslides that will alter its surface.
OSIRIS-APEX will allow scientists on Earth to observe these changes. Additionally, the OSIRIS-APEX spacecraft will dip toward the surface of Apophis – a “stony” asteroid made of silicate (or rocky) material and a mixture of metallic nickel and iron – and fire its engines to kick up loose rocks and dust. This maneuver will give scientists a peek at the composition of material just below the asteroid’s surface.
Other satellite projects, including those related to planetary defense, are also being planned.
Under the auspicious “NEAlight” project, a team from Julius-Maximilians-Universität Würzburg (JMU) and led by space engineer Hakan Kayal has revealed three concepts for such spacecraft. Each of the suggested satellites will aim to exploit this asteroid passage because Earth experiences just once such event every millennium.
The goal? To collect data that could help scientists better understand the solar system, and perhaps even aid in the development of defense measures against dangerous asteroids.
Yes, a wonderful opportunity to study this potentially hazardous object. Future generations will thank us for the information we gather in this close fly by.
Are Boeing going to be launching the rocket?
AFAF
In a twist of irony, the body is shaped like P’Nut the squirrel.
no impact….for at least 100 years
We have our own God of Darkness and impact is imminent.
Speaking of impacts-
Podcaster Joe Rogan ‘preys on fear’: ABC boss warns
Leftys don’t do irony
Whew! 100 years lets me off that hook! Now, I can get back to important things like saving the earth by driving an electric vehicle.
A close encounter.
Of the dangerous kind.
Will its gravitational influence affect satellite orbits ??
What will be the result on GPS etc ??
Only if it passes within a few feet of them.
There you are! Been on vacation?
Good questions.
Also, will it impact or damage any satellites?
I read twice. Pronouns were abused and nouns were omitted to confuse the issue: eg
“Due to swing close enough to the planet in 2029, the gravitational influence will be enough to cause tremors.”
Said tremors would occur on the asteroid, not on the Earth.
There’s a physics equation where the gravitational force is proportional to the mass of both objects and distance between them. Things nearer the asteroid will be affected more than things nearer the Earth because Earth is enormously more massive. A physics expert ought to calculate how close one would have to get to the asteroid before the asteroid’s Fg would equal Earth’s Fg at that point.
Assuming a density mid-way between rock (2.7 g/cm^3) and iron (7.9 g/cm^3) and further assuming Apophis can be approximated as a sphere of 340 m diameter, it is relatively easy to calculate its mass to be 1.09e11 kg and its surface gravity to be 0.00025 m/sec^2, or about 0.0026% that of Earth’s surface gravity.
Any object more than 1 km distant from Apophis would thus experience a tug (a gravitational acceleration) from it of less than 0.8 micro-g . . . in other words, the object wouldn’t even notice it passing by.
Answers for you: almost certainly no*, and absolutely nothing**.
*Space is HUGE, the odds of Apophis passing within 1 km of any satellite orbiting Earth is vanishingly small unless its orbital plane is exactly coplaner with Earth’s equatorial plane where GEO satellites reside, itself a vanishingly remote chance.
**GPS satellites fly at an altitude of approximately 20,200 km, but the above article states the closest Apophis will come to Earth is 32,000 km. Thus, LEO satellites and MEO satellites will not be affected by Apophis.
Thanks, I’m glad someone did the math. Looks right to me. Should be checked and put in article.
Thanks,
I wasn’t worried, just curious
“I wasn’t worried, just curious” . . . in my humble opinion, THAT, my friend, is an excellent explanation for why WUWT has the great readership that it does!
Not measurably affected
Does it count if you cannot measure it?
I read an article that musk is going to send up a colonizing spaceship and claim it for himself, becoming the first interplanetary-ist. Because globalist is just so passé. He’ll be worth $1.8T at that point anyway, so, gotta have a hobby.
That asteroid- I took a ride on it last time it whizzed by the Earth. 🙂 🙂 🙂
Looks like it got a LOT closer last time.
Or it’s a LOT smaller than expected!
A puff of gas on the surface of the asteroid from heating in the Sun could, of course, deflect it 30,000 km one way or the other…since it is 285 million km away yet..
I wonder if there’s been any thought of landing and “fastening” an instrument package on it?
We’ve got plenty of tools in the UK that we could spare
What they describe is tidal interaction between the planet and the asteroid. Tidal interaction transfers angular momentum between two objects and therefore has an effect on the asteroid’s orbit afterwards. The question is by how much and if the perturbed orbit brings the asteroid closer or not in a future encounter than it otherwise would be.
I don’t see the difference between this orbit and the type used to accelerate and redirect satellites getting a “gravity boost”. Given how close it will be, and the fact that it is “falling toward” Earth, surely it is going to affect the orbit a lot?
Year 2029. We are on the cups of 2025. 4 years in a semi chaotic solar system.
32,000 km. Nice we can calculate these things to that level of confidence (seriously).
However, stuff happens. Must we not also consider the possibility that some minor impact along the way alters the trajectory and do we have plans of how to deal with such a threat?
A nuclear explosion inside the lunar orbit will affect a lot of satellites.
It takes time to travel at non-relativistic speeds.
Seems we should be planning some kind of divert attitude control system lander, just in case.
340 m is big, not not out of technical reach today to nudge it.
Much better data exists to calculate the odds of an observed asteroid impacting Earth a certain day next year than to predict whether it will rain a certain day next year.
True that.
The Murphy effect, the random unexpected, can alter the trajectory.
That we are watching it good.
But what if? Should we not have a plan in place. 4 years to develop and deploy does not have a lot of margin, especially since as the object gets closer, the “nudge” must be greater.
The term “home planet” strikes me funny. Do we have another?
Must have, many people (particularly ‘The Glorious Leaders’ ) seem to be living on another planet !!!
I think the home planet wears white shirts and the away planet wears colors. If the game is on a supposedly neutral planet, the planet with better gambling odds in Las Vegas wears white.
From the above article:
“A recent study led by Ronald-Louis Ballouz from Johns Hopkins University Applied Physics Laboratory suggests that the asteroid 99942 Apophis may experience tremors—similar to earthquakes—due to Earth’s gravitational pull during its close flyby.”
Well, that statement needs to be considered very carefully . . . it’s time for a reality check.
Like all bodies in space on a “free fall” trajectory (i.e., subject only to gravitational forces and assuming the momentum exchange from solar radiation is insignificant) Apophis does not experience significant unidirectional stresses along the asteriod-Earth vector at any time and no matter how close it will come to Earth (as long as it remains outside of Earth’s sensible atmosphere that would cause noticeable drag). A rough analogy to see this is true is the fact that astronauts on the ISS remain “weightless” (i.e., don’t “feel the force of gravity”) despite being only about 400 km above Earth’s surface).
However, having said all of that, it is true that Apophis will experience tidal forces during its swing by Earth. Tidal forces are caused by gravity gradients as they develop radially (in accordance with (d/R)^2 scaling, where R is the distance from Earth’s center-of-mass to Apophis’ center-of-mass, and d is the asteroid’s physical distance along the gravitational vector from its center-of-mass) and laterally (in a plane perpendicular to the aforementioned instantaneous radial vector due to small angular variation in gravitational vectors across the physical size of the body).
Approximating both Earth and Apophis as spherical bodies with uniform densities (not necessarily the same densities), one can estimate the tidal forces—here, actually the differences in induced accelerations across Aphophis—at the stated worst-case, closest approach to Earth of 32,000 km:
— gravitational acceleration at 32,000 km altitude = 9.8 m/sec^2 at 6371 km (surface) *(6,371/(6,371+32,000))^2 = 0.27 m/sec^2
— d (maximum radial and lateral distances) = 340/2 m = +/- 170 m = +/- 0.17 km, since we are dealing with maximum distances from center-of-mass
— R (radial distance between Earth and Apophis CMs) = 6,371+32,000+0.17 = 38,400 km
— angle subtended by 0.17 km lateral separation at distance of 38,400 km = atan(0.17/38,400) = .00025 degrees = 4.4e-6 radians
So,
range of along-Earth-Apophis-vector tidal accelerations = 9.8*((6,371/38,400)^2-(6,371/(38,400.17)^2)*2 = 4.8e-6 m/sec^2 (multiplied by 2 because the total variation considers + and – distance deltas), and
range of lateral tidal accelerations in plane normal to above vector = 0.27*4.4e-6 *2 = 2.4e-6 m/sec^2 (again, multiplied by 2 because the total range considers +/- distance deltas)
Thus, it appears that the worst-case tidal acceleration differentials that Apophis will experience on its swing by Earth (assuming the above article’s stated numbers are correct) will be on the order of 0.5 micro-g radial and 0.2 micro-g lateral!
I am at a loss as to understand how such a minuscule tidal effect can cause “tremors—similar to earthquakes— . . . with simulations indicating significant surface changes” in the asteroid Apophis, as quoted in the above article. Perhaps the problems lies in the word “simulations”?
Nice. At least three readers here have taken university physics courses.
I’m going to check the “rocky” assumption.
It makes little difference to any of the conclusion but I wonder whether the asteroid is mostly rock or ice.
“Apophis is classified as an S-type, or stony-type asteroid made up of silicate (or rocky) materials and a mixture of metallic nickel and iron.“
2029.
Hmmm… Seems the earth is doomed in 2030 due to CO2, so why worry about a tiny pebble?
Don’t you know that “experts” have stated that the Earth is already doomed . . . we don’t have to wait for 2030 to come around:
In 2009 Prince Charles—you know, that renowned expert on climate change—issued a warning to the world that:
“I am firmly of the view that the next 18 months will decide our ability to keep climate change to survivable levels and to restore nature to the equilibrium we need for our survival”, Prince Charles speech at a Reception for Commonwealth Foreign Ministers, July 11, 2019
[note: July 11, 2019 + 18 months = mid-January 2021, so we passed that point-of-no-return nearly 4 years ago].
And long before Charles, the goofball, jumped onto the AGW/CAGW alarmist bandwagon we had similar dire predictions of Earth’s doom that obviously did not occur . . . from https://reason.com/2000/05/01/earth-day-then-and-now-2/ :
“Earth Day 1970 provoked a torrent of apocalyptic predictions. ‘We have about five more years at the outside to do something,’ ecologist Kenneth Watt declared to a Swarthmore College audience on April 19, 1970. Harvard biologist George Wald estimated that ‘civilization will end within 15 or 30 years unless immediate action is taken against problems facing mankind.’ ‘We are in an environmental crisis which threatens the survival of this nation, and of the world as a suitable place of human habitation,’ wrote Washington University biologist Barry Commoner in the Earth Day issue of the scholarly journal Environment . . . Imminent global famine caused by the explosion of the ‘population bomb’ was the big issue on Earth Day 1970. Then–and now–the most prominent prophet of population doom was Stanford University biologist Paul Ehrlich. Dubbed ‘ecology’s angry lobbyist’ by Life magazine, the gloomy Ehrlich was quoted everywhere. ‘Population will inevitably and completely outstrip whatever small increases in food supplies we make,’ he confidently declared in an interview with then-radical journalist Peter Collier in the April 1970 Mademoiselle. ‘The death rate will increase until at least 100-200 million people per year will be starving to death during the next ten years.’
‘Most of the people who are going to die in the greatest cataclysm in the history of man have already been born,’ wrote Ehrlich in an essay titled ‘Eco-Catastrophe!,’ which ran in the special Earth Day issue of the radical magazine Ramparts. ‘By…[1975] some experts feel that food shortages will have escalated the present level of world hunger and starvation into famines of unbelievable proportions.’ Other experts, more optimistic, think the ultimate food-population collision will not occur until the decade of the 1980s.’ Ehrlich sketched out his most alarmist scenario for the Earth Day issue of The Progressive, assuring readers that between 1980 and 1989, some 4 billion people, including 65 million Americans, would perish in the ‘Great Die-Off’. “
So many preaching alarmists asserting themselves to be “experts” . . . all proven so very wrong!
This situation was forewarned in the Bible:
“Professing themselves to be wise, they became fools.”
— Romans 1:22, King James Version (KJV)
All true and well known.
I guess I should have put a /sarc or a /humor mark on my post.
Nuke it dead center, blowing it to itsy-bitsy pieces plus several more explosions to clear an empty corridor that eventually will allow planet Earth be missed by anything bigger than a softball…The white paper ideas of solar pressure on its surface using mirrors or gravity “tractors” on a parallel path are just magical thinking science fiction.
If you could blow it in half a year ahead, each half separating by 10 km/hr (walking speed) at right angles to its trajectory, those halves would be 90,000 km apart by the time they get to Earth’s orbit leaving pretty big hole for Planet Earth in between….Of course a bit difficult to slice a rubble ball in half…..
Sounds like a good way to double—perhaps even increase by an order-of-magnitude—the chances of a large piece of Apophis hitting Earth. The is NO WAY to guide ALL the post-explosion debris away from one or more Earth-impact trajectories.
I’m not talking about 2029. I’m talking about how to reduce effects of 100% certainty impacts.
Also, there is a lack of understanding of how a nuclear explosion behaves in outer space. It’s mostly a burst of intense radiation that will vaporize the surface of an object on the explosion side. The vaporized material leaving the surface pushes the object the other direction in the same manner as rocket exhaust.
Hmmm . . . what are the odds that a nuclear “surface blast” will provide sizable impulsive thrust (from surface ablation) while at the same time the reactive “push” doesn’t cause the object whose surface it is detonated on to fracture apart?
Show your work.
Not so.
The exhaust from a well-designed chemical rocket exits in a unilateral direction after passing through a de Laval nozzle. Even ion and plasma rockets are designed to provide uniaxial exhaust streams, and thus a uniaxial thrust vector.
In comparison, a nuclear explosion of the surface of body having a characteristic surface radius much larger than the bomb’s dimensions will, in the vacuum of space, have the resulting surface ablation stream away in a generally hemispherical fashion. Such blast may integrate to provide a more-or-less average thrust in one direction, but it will be tremendously inefficient in doing so.
It’s probably difficult to break it up into safe pieces, sufficiently far apart.
Maybe some sort of excavator and railgun could simultaneously divert it and reduce its mass? Not sure what the energy source could be for such a task.
For those who wonder about the collision energy. There is wide variation in the estimated mass. Taking 21Mt moving at 6km/s gives kinetic energy of 3.8E17J. Lets call it 6,000Hiroshimas.
It could do a lot of damage.
Your kinetic energy value for a mass moving at a relative speed of 6 km/sec at impact is equivalent to a mass of 2.1e10kg = 21 million metric tons. However this mass is only 19% of my estimate of 1.09e11 kg for Apophis that I calculated in a previous post above.
It looks like you used a density of water (1g/cm^3) instead of value midway between the densities of rock and nickel/iron, stated to be the composition of Apophis in the above article.
Then it is worse than we think.
Maybe . . . maybe not.
Yes, correcting for the estimated density of Apophis, theoretically results in the energy equivalent of about 30,000 Hiroshima-size fission bombs, not the 6,000 mentioned by RickWill.
However, unlike the air burst of the single Hiroshima fission bomb, an impactor the size of the asteroid Apophis—particularly with it having the composite strength and ablation resistance associated with its asserted rock-metal composition—traveling at an asserted speed of 6 km/sec at impact will penetrate deep below Earth’s surface before releasing most of its kinetic energy as heat and pressure shock waves (mechanical energy expended fracturing subsurface rocks).
Only a TBD fraction of the kinetic energy will actually be deposited at the surface surrounding the impact point . . . not to say that such won’t cause complete destruction of surface features for tens to hundreds of km distance away from the point of impact, as well as creating severe shock waves and very likely ocean tsunamis that reverberate around the planet. Some energy is also transformed and put into the atmosphere in the form of ejecta and superheated gases from the crater created by the impact.
NASA has done quite a bit of research on the immediate consequences of asteroids of various sizes and compositions impacting Earth at high speed . . . for example, see https://www.nasa.gov/solar-system/asteroids/nasa-asteroid-experts-create-hypothetical-impact-scenario-for-exercise/ .
“Lets call it 6,000Hiroshimas.”
Rick, could you express that in terms we can all understand ??
Like the number of Olympic swimming pools, or London buses, or the size of Wales,
(;-))
That’s right . . . one needs to have been there to truly appreciate the significance of just one such bomb.
/sarc
File cabinets would be better.
;-))
Given expected ‘surface changes’ resulting from earth’s gravitational influence, are we happy that the scale, nature and effect of these on Apophis’ orbital mechanics are sufficiently well understood so that the non-dangerous assessment can be relied upon?
Asking for a friend. Well, all of them.
It was not based on a climate model, if that helps.