Apophis: Will It Hit the Earth?
Part 1

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Authored By  :
Bill Kochman

Published On :
January 12, 2023

Last Updated :
January 12, 2023

Defining Near-Earth Objects, Quantity Of NEOs, Near-Earth Asteroids, Potentially Hazardous Objects, Potentially Hazardous Asteroids, Spaceguard Foundation, NEAT, Sentry System, Palermo Technical Scale, Torino Scale, No Serious Threats Foreseen For Next 100 Years, Sentry Impact Risk Data Table, Calculating NEO Paths Isn't A Perfect Science, 101955 Bennu (1999 RQ36), 99942 Apophis (2004 MN4), Apophis Is Not A Threat To Earth, Apophis' Very Close 2029 Approach, Future Approaches Of Apophis, Apophis On Close Approach Data Table, Apep/Apophis: Egyptian God of Chaos, "Serpent From The Nile" And "Evil Dragon", Strategies To Deflect Asteroids, No Nukes

Some time ago, I had an opportunity to watch an interesting National Geographic documentary entitled "Asteroid That Hit Earth". As some of you will already know, and as National Geographic's documentary points out, at this current time, there are literally thousands of objects within our Solar System which are referred to as Near-Earth Objects. Those people who study these spacefaring bodies usually refer to them as NEOs. Near-Earth Objects include comets, asteroids and meteoroids that come into close proximity with Planet Earth, and certain man-made, solar-orbiting spacecraft as well.

Exactly how close must these Space objects come in order to qualify as a Near-Earth Object? The NASA website states that an NEO must have a perihelion -- or closest orbital distance from the Sun -- of less than 1.3 AU. An AU, or Astronomical Unit, is a unit of length that is used by astronomers that's equal to about 92,955,807 miles, or 149,597,871 kilometers. One AU also happens to be the mean distance of the Earth to the Sun. The NASA/JPL's CNEOS website states that as of the month of December, 2022, more than 31,000 Near-Earth Objects have been discovered. By the way, CNEOS stands for Center For Near Earth Object Studies.

As noted a moment ago, naturally-occurring Near-Earth Objects are divided between Near-Earth Comets, Near-Earth Asteroids and Near-Earth Meteoroids. According to the CNEOS website, as of December 24, 2022, a total of 118 Near-Earth Comets have been discovered. NASA states that in addition to having a perihelion of less than 1.3 AU, in order for a comet to be classified as an NEO/NEC, it must also be what is known as a short-period comet. That is to say, its orbital period must be less than two hundred years.

Concerning NEM's, or Near-Earth Meteoroids, while I was not able to find any information on the NASA website, Wikipedia states that they have a diameter of fifty meters or less.

According to the CNEOS website, just under 31,000 NEOs are Near-Earth Asteroids. As such, they are referred to as NEAs. When a new NEA has been detected, it is submitted to the Minor Planet Center where it is added to an extensive catalog. Located at the Smithsonian Institute's Smithsonian Astrophysical Observatory in Cambridge, the Minor Planet Center operates under the auspices of Division III of the International Astronomical Union. It is funded by a grant from NASA. The Minor Planet Center is globally recognized as the official organization which is in charge of collecting observational data for minor planets -- that is, asteroids -- and comets, calculating their orbits, and then disseminating this data via Minor Planet Circulars, in conjunction with the Central Bureau For Astronomical Telegrams. You can visit the Minor Planet Center website at:


To continue, of the currently known NEAs, 10,346 of them are known to have diameters of roughly 140 meters and larger. In addition, 858 NEAs are classified as being large asteroids, meaning that they are approximately one kilometer or larger in size. But size is not the only thing to consider when it comes to NEOs, NEAs and the like, as you will now see.

When a particular Near-Earth Object is determined to possibly be dangerous to the Earth, it is classified as a Potentially Hazardous Object, or PHO. In order to acquire PHO status, the NASA website states that an NEO must have a MOID -- or Earth Minimum Orbit Intersection Distance -- of 0.05 AU or less, as well as an absolute magnitude (H) of 22.0 or less. In simple terms, this means that said object must come within at least 4,650,000 miles -- or 7,480,000 kilometers -- of the Earth, and it must be larger than five hundred feet -- or about one hundred and fifty meters -- in diameter, in order to qualify as a PHO.

Being as most Near-Earth Objects are asteroids, a potentially dangerous asteroid is called a PHA, which is an acronym for Potentially Hazardous Asteroid. As of December 24, 2022, the CNEOS website lists 2,319 NEOs as being Potentially Hazardous Asteroids. But that is not all. There are also 152 PHAs which have an estimated diameter of one kilometer or larger. If you would like to see a breakdown of these statistics, please go to the following CNEOS webpage:


NEAs are further divided into four sub-groups. These are Atens, Apollos, Amors and Atiras. An asteroid belongs to a particular group based upon certain parameters that are associated with the trajectory of its orbit in relationship to the Earth. If you wish to learn more about this, please visit the following page on the CNEOS website:


Naturally, the potential for one of these NEOs to strike the Earth is of concern to both governments and scientists alike. As a result, in 1996 a global network of earth-based observatories was set up in order to monitor these objects. This global endeavor to discover, identify and monitor NEOs is referred to as the Spaceguard Foundation. Apparently, the name of the foundation finds it origin in Arthur C. Clarke's classic 1972 science fiction novel "Rendezvous With Rama", which I read -- and greatly enjoyed -- many years ago. The Spaceguard Foundation is a non-political, non-profit entity. It is based in Frascati, Italy at the ESA Centre for Earth Observation. ESA is the European Space Agency.

Just prior to the formation of the Spaceguard Foundation, NASA and the Jet Propulsion Laboratory set up a similar NEO program called Near Earth Asteroid Tracking, or NEAT. This program was in operation from 1995 until 2007. In addition to NEAT, NASA and the Jet Propulsion Laboratory also operate an automated monitoring system called the JPL Sentry System. Concerning this NEA monitoring system, on its website, NASA states in part:

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"Sentry is a highly automated collision monitoring system that continually scans the most current asteroid catalog for possibilities of future impact with Earth over the next 100 years. Whenever a potential impact is detected, it will be analyzed and the results immediately published . . ."

"Every day, observations and orbit solutions for Near-Earth Asteroids (NEAs) are received from the Minor Planet Center (MPC) in Cambridge, Massachusetts. Once classified as an NEA, the asteroid is thereafter given automatic orbit updates within our Sentry system. A new orbit solution for an NEA is computed whenever new optical or radar observations for that object become available."

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Of course, not all Near-Earth Asteroids pose the same degree of threat to the Earth. With that in mind, different scales have been designed to classify each NEO, or NEA. The first scale is called the Palermo Technical Scale. This scale is used internally by the International Astronomical Union to grade the potential impact threat of an NEA. Scientists who use the Palermo Technical Scale rely upon various factors to measure the importance of a potential impact. These are the impact date, the impact energy -- meaning what degree of damage may occur should an impact actually occur -- and the impact probability -- meaning the likelihood that the impact will actually occur. The Palermo Technical Scale is a very complex tool which employs advanced mathematics and science in order for space scientists to arrive at their conclusions, and is therefore not meant for the public.

In the event that NASA, the IAU, etc., determine that an NEA poses a significant threat to the Earth, they'll use a much more simplified scale -- referred to as the Torino Scale, or the Torino Impact Hazard Scale -- in order to communicate their findings to the general public. However, unlike the Palermo Technical Scale, the Torino Scale is only used to convey information regarding NEAs which have the potential for impacting the Earth within the next one hundred years; the reason being that NEAs which possess impact potential outside of the 100-year time frame -- such as 1999 RQ36 -- would be of little interest to the current public. Thus, the Torino Scale is purposely designed to be a more simplified scale compared to its technical cousin, the Palermo Technical Scale.

If you are reading this article in HTML format on the Bill's Bible Basics website, you can see a representation of the Torino Scale below, taken from the NASA website:

If you are interested in viewing a much larger -- or more easily readable -- table of the Torino Impact Hazard Scale, please visit the URL below on the CNEOS website:


At this point, you may possibly be wondering exactly how many Near-Earth Asteroids pose a potential impact threat to the planet Earth. In contrast to what some headline-grabbing news reports, sensationalistic Hollywood movies, misguided social media addicts, and self-styled, wannabe prophets would like you to believe, according to the information that can be found on the CNEOS website, at this current time, and in fact during the next 100 years, NO SERIOUS THREATS are foreseen. You can verify this information for yourself by carefully examining the Sentry Impact Risk Data table which is found on the CNEOS website at the following URL:


When you arrive at the above page, click on the number that you see under the "Impact Probability (cumulative)" column. Doing so will bring up a small window which will explain to you in more layman's terms what the probability is of that particular object hitting the Earth. Please also notice that under the two "Palermo Scale" columns, all of the numbers are negative. Likewise, the "Torino Scale" column shows all zeroes. To learn more about a particular object, click or tap on its name in the "Object Designation" column. In order to better understand the Sentry Impact Risk Data table, and to view it in its proper context, you may wish to read the introductory page of the Impact Risk section of the CNEOS website at the following URL:


As you'll learn there, even the scientists and mathematicians who run the Sentry collision monitoring system, clearly state that calculating the paths of NEOs, and their proximity to the Earth at their closest approach, isn't a perfect science. As more observations are conducted, the numbers can change, and new NEOs will be added to the table, while others will be transferred to the "Removed Objects" table, as their impact risk lowers. It is just the nature of the process.

Please note that the information on the aforementioned table only covers the next one hundred years. While astronomers are currently not predicting any impacts with the Earth, it should be noted that there are a number of variables which affect their conclusions. First of all, as we have already seen, information that is made available to the public is based on the Torino Scale. This means that even if there were a potential impact threat one hundred years from now, or thereafter, we the public would not know about it. In fact, according to the information I have researched, there are a number of Near-Earth Asteroids which are of interest to astronomers, precisely because they possess varying degrees of impact potential after that date, even if that potential is rather small.

For example, discovered in 1999, the asteroid designated as 101955 Bennu (1999 RQ36), is about 490 meters in diameter, and is listed as a PHA. It has a 1 in 1,800 chance of striking the Earth at some point in the future. In other words, there is a 99.943% chance the asteroid will TOTALLY MISS the Earth.

Another asteroid which was previously of considerable concern was 99942 Apophis (2004 MN4). Discovered in 2004, this NEA is estimated to be about 350-390 meters in diameter. It's listed as a PHA, or Potentially Hazardous Asteroid. Shortly after its discovery in June 2004, 99942 Apophis was classified as a 4 on the Torino Scale, which is the highest rating an NEA had ever reached. Early observations suggested a 2.7% probability that it might strike the Earth on April 13, 2029. However, as additional observations were made, the possibility of a direct impact on the Earth in 2029 was eventually eliminated. But if it were to directly strike the Earth, the Sentry Risk Table estimates that Apophis would impact Earth with kinetic energy equivalent to 1,200 megatons of TNT! That is no small explosion!

Nevertheless, despite the threat level being downgraded, that still was not the end of the story for asteroid Apophis. That is because there yet remained some indications that whatever happened with the 2029 passage, might possibly result in a direct strike on April 13, 2036. However, once again, further observations removed that possibility, and by August of 2006, Apophis had been dropped to a rating of zero on the Torino Scale.

In fact, when I tried to find Apophis on the aforementioned Sentry Impact Risk Data table, it was nowhere to be found, regardless of what object designation I used for it. This gave me the impression that NASA/JPL and the CNEOS website apparently no longer consider Apophis to be of any great significance, or at least believe that it has zero chance of directly impacting the Earth during the next century. Just a few minutes ago, as I continued to study this issue, I found the following information on the Wikipedia website:

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". . . on March 25, 2021, the Jet Propulsion Laboratory announced that Apophis has no chance of impacting Earth in the next 100 years. The uncertainty in the 2029 approach distance has been reduced from hundreds of kilometers to now just a couple of kilometers, greatly enhancing predictions of future approaches. Apophis was removed altogether from the Sentry Risk Table the next day."

----- End Quote -----

Based on the above quote from Wikipedia, I went back to the CNEOS website to the "Removed Objects" page. As I mentioned earlier, once an object -- meaning a Near-Earth Object -- has been determined to have a very low or zero impact risk, it is dropped from the Sentry Impact Risk Data table, and placed on the Sentry Removed Objects table instead. You will find the latter table at the following URL:


Well, I searched backwards from the current year to the year 2004, and I was unable to find the Apophis (2004 MN4) removal listing anywhere, so I am not sure what to think of that. As I said, the Wikipedia website states that Apophis was removed from the Sentry Impact Risk Data table. I was able to confirm this point in an online EuroNews article dated March 28, 2021, and called "Good news: Asteroid Apophis won't hit Earth for at least 100 years, says NASA". In the article, Davide Farnocchia of the Center for Near-Earth Object Studies -- CNEOS -- states the following:

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"A 2068 impact is not in the realm of possibility anymore, and our calculations don't show any impact risk for at least the next 100 years . . . With the support of recent optical observations and additional radar observations, the uncertainty in Apophis’ orbit has collapsed from hundreds of kilometers to just a handful of kilometers when projected to 2029. This greatly improved knowledge of its position in 2029 provides more certainty of its future motion, so we can now remove Apophis from the risk list."

----- End Quote -----

Upon reading the EuroNews article, I was not aware of the fact that the asteroid was also expected to make a close approach -- or possibly even a direct impact -- in 2068. However, upon more closely examining the information that I found on the Wikipedia website, I discovered the following:

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2029 close approach

The closest known approach of Apophis occurs at April 13, 2029 21:46 UT, when Apophis will pass Earth closer than geosynchronous communication satellites, but will come no closer than 31,600 kilometres (19,600 mi) above Earth's surface. Using the June 2021 orbit solution which includes the Yarkovsky effect, the 3-sigma uncertainty region in the 2029 approach distance is about ±3.4 km. The distance, a hair's breadth in astronomical terms, is five times the radius of the Earth, ten times closer than the Moon, and closer than more than 500 geostationary satellites currently orbiting the earth. It will be the closest asteroid of its size in recorded history. On that date, it will become as bright as magnitude 3.1 (visible to the naked eye from rural as well as darker suburban areas, visible with binoculars from most locations). The close approach will be visible from Europe, Africa, and western Asia. During the approach, Earth will perturb Apophis from an Aten-class orbit with a semi-major axis of 0.92 AU to an Apollo-class orbit with a semi-major axis of 1.1 AU. Perihelion will lift from 0.746 AU to 0.894 AU and aphelion will lift from 1.099 AU to 1.31 AU.

2036 approaches

In 2036 Apophis will approach the Earth at a third the distance of the Sun in both March and December. Using the 2021 orbit solution, the Earth approach on March 27, 2036, will be no closer than 0.3089 AU (46.21 million km; 28.71 million mi; 120.2 LD), but more likely about 0.3097 AU (46.33 million km; 28.79 million mi). The planet Venus will be closer to Earth at 0.2883 AU (43.13 million km; 26.80 million mi; 112.2 LD) on May 30, 2036.

2051 approach

Around April 19–20, 2051, Apophis will pass about 0.04 AU (6.0 million km; 3.7 million mi) from Earth and it will be the first time since 2029 that Apophis has passed within 10 million km of Earth.


In the 2060s Apophis will approach Earth in September 2066, and then from February 2067 to December 2071 Apophis will remain further from Earth than the Sun is. On April 12, 2068, JPL Horizons calculates that Apophis will be about 1.864 ± 0.003 AU (278.85 ± 0.45 million km) from Earth, making the asteroid much further than the Sun.

----- End Quote -----

Concerning the aforementioned 2029 passage of Apophis, one rather amazing thing about it is the fact that it will be so close in proximity to the Earth, that in some areas of the world, people will actually be able to see it with the naked eye. Sadly, that doesn't appear to be the case for the island of Guam in the Mariana Islands, where I happen to live. The EuroNews article I shared previously also states the following:

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Some Earth dwellers will have the chance to see Apophis with their own eyes in April 2029, when it will pass the planet at the somewhat uncomfortably close distance of 20,000 miles - closer than the distance of geosynchronous satellites.

It will be visible to observers on the ground in the Eastern Hemisphere without the aid of a telescope or binoculars, NASA said.

----- End Quote -----

While in astronomical terms, asteroid Apophis passing within some 20,000 miles of the Earth is certainly a rather close passage, in recent decades, there have been a few others, but they have not come nearly as close as Apophis will do in 2029. For example, on May 19, 1996 Asteroid 1996 JA1 passed the Earth at a distance of about 281,000 miles -- or 450,000 kilometers -- which is about the distance to the Moon. With a diameter of about 500 meters, 1996 JA1 is probably the largest asteroid to pass so close to the Earth. In September of the year 2000, Asteroid QW7 came within some four million kilometers of the Earth, or about 2,485,485 miles. Lastly, on July 3rd of 2006, Asteroid 2004 XP14 passed by the Earth at a distance of about 268,624 miles -- or roughly 430,000 kilometers -- which is about 1.1 times the average distance of the Moon from the Earth. It is estimated to be a quarter mile to half a mile wide, and is classified as a PHA.

Returning to our discussion concerning Apophis, while I was unable to find 99942 Apophis on CNEOS's "Removed Objects" list, on the Close Approach Data table, I was able to find a total of fourteen passages of the asteroid, both from the past, as well as into the future. I am not sure why the 2036 and 2068 passages are not mentioned in this table:

Close Approach (CA)
CA Distance
Nominal (au)
CA Distance
Minimum (au)

99942 Apophis (2004 MN4) 1907-Apr-13 01:12 ± 00:02 0.02861 0.02860
99942 Apophis (2004 MN4) 1939-Dec-18 16:26 ± < 00:01 0.05985 0.05985
99942 Apophis (2004 MN4) 1949-Apr-14 11:30 ± < 00:01 0.02796 0.02796
99942 Apophis (2004 MN4) 1957-Apr-01 03:20 ± < 00:01 0.07540 0.07539
99942 Apophis (2004 MN4) 1972-Dec-24 11:52 ± < 00:01 0.07924 0.07924
99942 Apophis (2004 MN4) 1980-Dec-18 01:52 ± < 00:01 0.07213 0.07213
99942 Apophis (2004 MN4) 1990-Apr-14 20:44 ± < 00:01 0.03293 0.03293
99942 Apophis (2004 MN4) 1998-Apr-14 19:46 ± < 00:01 0.02439 0.02439
99942 Apophis (2004 MN4) 2004-Dec-21 09:25 ± < 00:01 0.09638 0.09638
99942 Apophis (2004 MN4) 2013-Jan-09 11:43 ± < 00:01 0.09666 0.09666
99942 Apophis (2004 MN4) 2029-Apr-13 21:46 ± < 00:01 0.00025 0.00025
99942 Apophis (2004 MN4) 2051-Apr-20 01:55 ±    08:24 0.04146 0.03981
99942 Apophis (2004 MN4) 2102-Sep-11 20:32 ±    15:55 0.02343 0.02249
99942 Apophis (2004 MN4) 2116-Apr-12 17:50 ± 7_14:41 0.01946 0.00101

If you are interested in such things, you can examine and use the CNEOS's Close Approach Data table for yourself at the following URL. Make sure to adjust the Table Settings according to your personal preferences using the pull-down menus:


It was in fact when I first became aware of Apophis in 2019, that I began writing this current article. After all, based on the limited information I possessed at the time, it seemed that Apophis might possibly be of some Biblical significance. I was also drawn to Apophis due to the fact that its name is derived from the ancient Egyptian god of chaos, Apep, which in the ancient Greek language is Apophis. Apophis has been depicted in art as a great serpent, and conferred with titles such as "Serpent from the Nile" and "Evil Dragon". He's also been depicted as a crocodile as well. More on these points a bit later in this article.

To continue, as I further studied the matter concerning this particular asteroid, and came to the realization that Apophis is no longer the threat which had first been suggested, I put off finishing this article until this current time. Yet while according to astronomers, Apophis no longer poses a serious threat to the Earth for the foreseeable future, nevertheless, being as there may be -- and probably will be -- significant threats from other Near-Earth Objects at some point in the future, it should come as no surprise that governments and men of science have devised a number of plans to eliminate any potential NEA threats in the future, by deflecting asteroids and other NEOs away from the Earth.

One such project which was proposed by the European Space Agency was called the Don Quijote Mission. This experiment to deflect asteroids away from the Earth was to consist of two spacecrafts: the Hidalgo and the Sancho. The strategy was for Hidalgo to crash into Apophis, while Sancho was to observe the collision and record any changes in the trajectory of the asteroid. However, this mission never got beyond the initial study stage. According to the Wikipedia website, other plans to deflect threatening asteroids include the following:

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Studies by NASA, ESA, and various research groups in addition to the Planetary Society contest teams, have described a number of proposals for deflecting Apophis or similar objects, including gravitational tractor, kinetic impact, and nuclear bomb methods.

On December 30, 2009, Anatoly Perminov, the director of the Russian Federal Space Agency, said in an interview that Roscosmos will also study designs for a possible deflection mission to Apophis.

On August 16, 2011, researchers at China's Tsinghua University proposed launching a mission to knock Apophis onto a safer course using an impactor spacecraft in a retrograde orbit, steered and powered by a solar sail. Instead of moving the asteroid on its potential resonant return to Earth, Shengping Gong and his team believe the secret is shifting the asteroid away from entering the gravitational keyhole in the first place.

On February 15, 2016, Sabit Saitgarayev, of the Makeyev Rocket Design Bureau, announced intentions to use Russian ICBMs to target relatively small near-Earth objects. Although the report stated that likely targets would be between the 20 to 50 metres in size, it was also stated that 99942 Apophis would be an object subject to tests by the program.

In October 2022, a method of mapping the insides of a potentially problematic asteroid, such as 99942 Apophis, in order to determine the best area for impact was proposed.

----- End Quote -----

In addition to directly impacting a threatening asteroid with rockets such as ICBMs, a few other methods of deflection have been suggested as well. For example, one approach would be to use a solar mirror to reflect light from the Sun on to the asteroid, so as to boil away parts of the object. The hope is that the stream of gases would sufficiently move the asteroid so that it would no longer be in the Earth's path.

Yet another suggested proposal has been to cover the surface of an asteroid with paint or some other material which would either absorb or reflect light. The idea is that heating or cooling parts of the asteroid would result in changing its orbit just enough so that it would miss the Earth.

Instead of smashing one or more missiles into an asteroid such as Apophis, another proposal suggests actually landing a rocket on the asteroid, and then using chemicals which are found on the asteroid to propel it in a different direction, thus avoiding a collision with the Earth.

Some of you may be wondering why no one has suggested using nuclear warheads to simply destroy a threatening asteroid before it reaches the Earth. Well, if you have watched enough Outer Space disaster movies such as "Armageddon" and "Deep Impact", you may already know the answer to this question. The simple fact is that doing so could inadvertently result in generating thousands of smaller objects which would be on a similar course as the original asteroid. In short, simply blowing up an asteroid could potential compound the problem.

Please go to part two for the conclusion of this article.

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