Astronomy

Size and Mass of a typical “small” asteroid that impacts the Earth?

Size and Mass of a typical “small” asteroid that impacts the Earth?


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I'm looking for some realistic data about the size (in meters) and mass (in kg) of a typical small asteroids that impact the Earth, without disintegrating in the atmosphere.

Any suggestion ?


For the asteroid not to break up it needs to either be big, or tough. You can experiment with the impact effects calculator but you should notice that a rocky asteroid with a diameter of less than about 1km will partially break up on impact with the atmosphere, and there may be multiple craters formed.

If the asteroid is less than about 100m in diameter than the breakup will be complete enough that the resulting meteorites will fall at terminal velocity, and won't form craters in rock.

Iron meteorites are tougher, but even these are likely to break up if they are less than 500m in diameter.

Needless to say, these are not small events, and we have never actually witnessed any object hitting the Earth that is large enough to make it through our atmosphere in one piece.

The direct answer to the question is that there are no typical small impacts of bodies that don't break up. The Barringer "meteor crator" impactor was an iron asteroid, with a diameter of about 40 or 50m, that broke up on impact with the atmosphere, and fell in a circle of about 150m in diameter, forming the 1km diameter crater we see now. The mass of the impactor was about 1 to 2 million tonnes. It hit the atmosphere at about 15 to 17 km/s but by the time it reached Earth, it had slowed to less than 12 km/s. It exploded with the energy of about 10 Megatonnes of TNT. The dispersal of the fragments was not enough to from several craters. See a barringer type impact Or read about the impact


It is best summed up by this graph of meteorite diameter versus frequency of impact, divided by the probability of atmosphere traversal.

Micrometeorites (particles normally less than 1 mm in size) constitute the main part of the flux of extraterrestrial matter accreting on Earth (1-3). (from arctic samples)

Over the whole surface area of Earth, there's 18,000 to 84,000 meteorites bigger than 10 grams per year. (study by P. A. Bland and was published in Monthly Notices of the Royal Astronomical Society.)


Asteroid 2020 SW Flew Safely Past Earth Today

2020 SW safely flew past Earth today at a distance of about 22,000 km. Image credit: University of Colorado.

2020 SW was discovered on September 18, 2020, by astronomers using the NASA-funded Catalina Sky Survey in Arizona.

Follow-up observations confirmed its orbital trajectory to a high precision, ruling out any chance of impact.

A team of astronomers from the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory immediately determined that 2020 SW will make its closest approach on September 24, 2020 over the southeastern Pacific Ocean.

Based on its brightness, the asteroid was estimated to be between 5 and 10 m (15-30 feet) in diameter.

Although it’s not on an impact trajectory with Earth, if it were, the space rock would almost certainly break up high in the Earth’s atmosphere, becoming a bright meteor known as a fireball.

“There are a large number of tiny asteroids like this one, and several of them approach our planet as close as this several times every year,” said CNEOS director Dr. Paul Chodas.

“In fact, asteroids of this size impact our atmosphere at an average rate of about once every year or two.”

After today’s close approach, 2020 SW will continue its journey around the Sun.

The asteroid will not return to the Earth-Moon system until 2041, when it will make a much more distant flyby.

“The detection capabilities of NASA’s asteroid surveys are continually improving,” Dr. Chodas said.

“We should now expect to find asteroids of this size a couple days before they come near our planet.”


Asteroid Bennu Has a Chance for Gigaton Impact Around 2175-2199

The Palermo Technical Impact Hazard Scale for asteroids is a logarithmic scale used by astronomers to rate the potential hazard of impact of a near-earth object (NEO). It combines two types of data—probability of impact and estimated kinetic yield—into a single “hazard” value. A rating of 0 means the hazard is equivalent to the background hazard (defined as the average risk posed by objects of the same size or larger over the years until the date of the potential impact). A rating of +2 would indicate the hazard is 100 times greater than a random background event. Scale values less than −2 reflect events for which there are no likely consequences, while Palermo Scale values between −2 and 0 indicate situations that merit careful monitoring. A similar but less complex scale is the Torino Scale, which is used for simpler descriptions in the non-scientific media.

On Jan. 27, 2020 scientists using a telescope on Mauna Loa in Hawaii spotted an asteroid that has been classified as a potentially hazardous asteroid. It is called 2020 BX12 and it passed within 2.7 million miles and will not get any closer pass over the next century. 2020 BX12 also has a moon. The larger rock is at least 540 feet (165 meters) across, and the smaller one is about 230 feet (70 m) wide. They appeared to be separated by about 1,200 feet (360 meters).

As of December 2019, two asteroids have a cumulative Palermo Scale value of above -2: (29075) 1950 DA (-1.42) and 101955 Bennu (-1.71). A further three have cumulative Palermo Scale values of above -3: 1979 XB (-2.82), 99942 Apophis (-2.83), and 2000 SG344 (-2.86). 25 more have a cumulative Palermo Scale value of above -4, three of them having been discovered in 2019.

Bennu has a cumulative 1-in-2,700 chance of impacting Earth between 2175 and 2199. It is named after the Bennu, the ancient Egyptian mythological bird associated with the Sun, creation, and rebirth. 101955 Bennu has a mean diameter of 490 m (1,610 ft 0.30 mi) and has been observed extensively with the Arecibo Observatory planetary radar and the Goldstone Deep Space Network. If an impact were to occur, the expected kinetic energy associated with the collision would be 1,200 megatons in TNT equivalent (for comparison, TNT equivalent of Little Boy was approx 15 kiloton).

(29075) 1950 DA, provisional designation 1950 DA, is an asteroid, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.1 kilometers (0.68 miles) in diameter. It has about 5 times the mass of Bennu.

1950 DA had the highest known probability of impacting Earth. In 2002, it had the highest Palermo rating with a value of 0.17 for a possible collision in 2880. Since that time, the estimated risk has been updated several times. In December 2015, the odds of an Earth impact were revised to 1 in 8,300 (0.012%) with a Palermo rating of −1.42. As of 2018, It is listed on the Sentry Risk Table with the highest cumulative Palermo rating. 1950 DA is not assigned a Torino scale rating, because the 2880 date is over 100 years in the future. As of the 7 December 2015 solution, the probability of an impact in 2880 is 1 in 8,300 (0.012%).

The energy released by a collision with an object the size of 1950 DA would cause major effects on the climate and biosphere, which would be devastating to human civilization. The discovery of the potential impact heightened interest in asteroid deflection strategies. It would impact with about 10 gigatons of force.

The near-Earth object (89959) 2002 NT7 was the first near-Earth object detected by NASA. It was given a positive rating on the scale of 0.06 which indicated a higher-than-background threat. The value was subsequently lowered after more measurements were taken. 2002 NT7 is no longer considered to pose any risk and was removed from the Sentry Risk Table on 1 August 2002.

For a brief period in late December 2004, with an observation arc of 190 days, asteroid (99942) Apophis held the record for the highest Palermo scale values, with a value of 1.10 for a possible collision in the year 2029. The 1.10 value indicated that a collision with this object was considered to be almost 12.6 times as likely as a random background event: 1 in 37 instead of 1 in 472. With further observation through 2016 there is no significant risk from Apophis at any of the dates in question.

SOURCES – NASA JPL Center for NEO Studies (CNEOS), Wikipedia
Written By Brian Wang, Nextbigfuture.com

Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.

Known for identifying cutting edge technologies, he is currently a Co-Founder of a startup and fundraiser for high potential early-stage companies. He is the Head of Research for Allocations for deep technology investments and an Angel Investor at Space Angels.

A frequent speaker at corporations, he has been a TEDx speaker, a Singularity University speaker and guest at numerous interviews for radio and podcasts. He is open to public speaking and advising engagements.


433 Eros

This picture of Eros, the first of an asteroid taken from an orbiting spacecraft, is a mosaic of four images obtained by NASA's NEAR mission immediately after the spacecraft's insertion into orbit. Image Credit: NASA/JPL

Discovery

433 Eros was discovered on Aug. 13, 1898 by Gustav Witt, director of the Urania observatory in Berlin, and independently on the same day by Auguste H.P. Charlois at Nice, France.

Witt's discovery was the accidental byproduct of a two-hour photographic exposure he conducted of a different asteroid: 185 Eunike. Along with Eunike, the image he produced showed a 0.4-mm image trail, and observations on the following evening identified the object as one of unusually high apparent motion on the sky. Less than two weeks later, Adolf J. Berberich computed that the object's orbit brought it well inside the orbit of Mars, making it the first-known near-Earth asteroid.

Overview

Eros is famous as the first asteroid to be orbited by a spacecraft, and as the first one on which a spacecraft landed. But it was important to astronomers as far back as 1898, when it became the first near-Earth asteroid (NEA) to be discovered.

The NEAR spacecraft first flew by Eros on Dec. 23, 1998 at a distance of about 2,400 miles (about 3,800 kilometers) and found that the asteroid was smaller than expected and had two medium-sized craters, a long surface ridge and a density similar to that of Earth's crust. After several trajectory adjustments, NEAR finally moved into orbit around Eros on Valentine's Day (befitting an asteroid named for the Greek god of love), Feb. 14, 2000.

After nearly a year in orbit, during which time the spacecraft was renamed "NEAR Shoemaker" in honor of astrogeology pioneer Eugene Shoemaker, the mission carried out humanity's first asteroid landing on Feb. 12, 2001. Eros was 196 million miles (315 million kilometers) from Earth at the time.

The spacecraft wasn't expected to survive the landing but its instruments remained operational, leading to yet another milestone. "This is the first gamma-ray experiment that has ever been done on the surface of a body other than Earth," said Dr. Jacob Trombka of NASA's Goddard Space Flight Center. "In fact, we can say it's the first feasibility study of how to design an instrument to be used on a rover that could select samples from the surface, look for the presence of water, or map the surface for the purpose of future mining."

The spacecraft issued its final transmission from the surface of Eros on Mar. 1, 2001.

Before ground-based radar was available to observe extraterrestrial bodies, astronomers used Eros to help them calculate the mass of the Earth-moon system and the value of the astronomical unit (the AU, equivalent to the distance from the sun to Earth's orbit).

Eros is an S-type asteroid, the most common type in the inner asteroid belt. It's a typical member of the Amors group of NEAs, which cross Mars' orbit but do not quite reach that of Earth. Unlike the much more numerous main-belt asteroids between Mars and Jupiter, NEAs are thought to be dead comets or fragments from main-belt asteroid collisions.

Eros was observed with ground-based telescopes for a century before our spacecraft gave us a close-up look, and was the subject of a worldwide observation campaign during its close approach to Earth in 1975, when it was only 14 million miles (22 million kilometers) away.

How Eros Got Its Name

In a break with tradition at the time, the asteroid was given a male name: Eros, son of Mercury and Venus and god of love in Greek mythology.


Tsunamis, wildfires followed dinosaur-killing impact

Image via Curtin University.

Scientists have long believed that the end of the dinosaurs came as a result of a giant asteroid that crashed into Earth about 66 million years ago. Now, a new study by an international team of geologists, published in the peer-reviewed journal Proceedings of the National Academy of Sciences on September 9, 2019, has found hard evidence of the theory by analyzing the hundreds of feet of rocks that filled the impact crater within the first 24 hours after impact.

The geologists say the evidence shows that the asteroid impact caused wildfires, triggered tsunamis and blasted so much sulfur into the atmosphere that it blocked the sun, which caused the global cooling that ultimately doomed the non-avian dinosaurs.

The researcher drilled 1,640 to 4,265 feet (500 to 1,300 meters) into the seafloor below the Chicxulub crater off the coast of what’s now Mexico, in order to extract core samples of the rocks which filled the crater within 24 hours after the asteroid hit.

Location of Chicxulub crater. Image via Wikipedia.

Sean Gulick, a research professor at the University of Texas Institute for Geophysics (UTIG) at the Jackson School of Geosciences, is lead author of the study. Gulick said in a statement:

It’s an expanded record of events that we were able to recover from within ground zero. It tells us about impact processes from an eyewitness location.

Curtin University geochemist Kliti Grice is a study co-author. She said:

The asteroid impact that formed the Chicxulub crater on the Yucatán Peninsula in Mexico, where this research was carried out, is thought to be the cause of the late Cretaceous Period mass extinction event which led to 76 per cent of all plant and animal species world-wide, including all non-flying dinosaurs, being killed off.

According to the researchers, most of the material that filled the crater within hours of the asteroid’s impact was either produced at the impact site, or swept in by seawater pouring back into the crater. Just one day deposited about 425 feet (130 meters) of material, said the geologists, a rate that’s among the highest ever encountered in the geologic record. That breakneck rate of accumulation means that the rocks in the crater record what was happening within and around the crater in the minutes and hours after the impact.

Researchers estimate the asteroid hit with the equivalent power of 10 billion atomic bombs of the size used in World War II. The blast ignited trees and plants that were thousands of miles away and triggered a massive tsunami that reached as far inland as Illinois. Inside the crater, researchers found charcoal and a chemical biomarker associated with soil fungi within or just above layers of sand that shows signs of being deposited by resurging waters. This suggests that the charred landscape was pulled into the crater with the receding waters of the tsunami.

A portion of the drilled cores from the rocks that filled the crater. Scientists found melted and broken rocks such as sandstone, limestone and granite — but no sulfur-bearing minerals, despite the area’s high concentration of sulfur containing rocks. This finding suggests that the impact vaporized these rocks forming sulfate aerosols in the atmosphere, causing cooling on the global scale. Image via International Ocean Discovery Program.

One of the most important findings from the research is what was missing from the core samples. The area surrounding the impact crater is full of sulfur-rich rocks. But there was no sulfur in the core. This lack supports the idea that when the asteroid hit, sulfur from the crater was vaporized into the atmosphere, where it wreaked havoc on the Earth’s climate, reflecting sunlight away from the planet and causing global cooling. Researchers estimate that at least 325 billion metric tons would have been released by the impact. To put that in perspective, that’s about four orders of magnitude greater than the sulfur that was spewed during the 1883 eruption of Krakatoa — which cooled the Earth’s climate by an average of 2.2 degrees Fahrenheit (1.2 degrees Celsius) for five years.

Although the asteroid impact created mass destruction at the regional level, it was this global climate change that caused a mass extinction, killing off the dinosaurs along with most other life on the planet at the time, Gulick said.

The real killer has got to be atmospheric. The only way you get a global mass extinction like this is an atmospheric effect.

Geologists Sean Gulick, of University of Texas and Joanna Morgan, of Imperial College London, on the 2016 research expedition that retrieved cores from the submerged and buried impact crater. Image via The University of Texas at Austin/Jackson School of Geosciences.

Bottom line: A new study analyzed rock from deep within the Chicxulub impact crater to learn what happened immediately after the asteroid impact that doomed the dinosaurs.


Asteroid Impact


A bullet shot out of a high-powered rifle can travel at speeds up to 2500 miles per hour. In one second it would travel one kilometer in distance. Whatever it strikes would be pulverized on impact.

Now imagine a boulder-sized asteroid arriving from outer space, and hitting the earth at twenty times this speed (roughly 20 kilometers per second). The impact energy released would be comparable to an atomic bomb exploding.

Now imagine an asteroid that is one kilometer in diameter, weighing roughly 1.4 billion tonnes, hitting the earth at this speed. The force of impact would be so great that it would mostly vaporize the asteroid. And the impact energy released would be so tremendously powerful that it would be much greater than all the energy released if all the atomic bombs in the world went off at once. It would truly be like Armageddon.

You can easily estimate the impact energy of an asteroid. You do this by calculating the kinetic energy of the asteroid just before it strikes the earth. This is equal to the impact energy.

Kinetic Energy = (1/2)MV 2

Where:

M is the mass of the asteroid just before it strikes the earth

V is the velocity of the asteroid just before it strikes the earth

For example, consider an asteroid that is one kilometer in diameter and weighs 1.4 billion tonnes (M = 1.4×10 12 kilograms), and is traveling at 20 kilometers per second (V = 20,000 m/s). The kinetic energy would be equal to (1/2)×1.4×10 12 ×(20,000) 2 = 2.8×10 20 Joules.

It is hard to imagine such immense energy. But over the course of geologic time, the planet earth has been struck many times by numerous asteroids, some very large. In fact, it is believed that the extinction of the dinosaurs was likely caused by a massive asteroid (or comet) impact and its catastrophic effects on the global environment.

A popular tourist attraction is the Barringer Crater in the Arizona desert. It is about 1200 meters in diameter and 170 meters deep. The crater is shown below.


This crater was created by an asteroid impact about 50,000 years ago. It is estimated that the asteroid was about 50 meters across.

Many asteroids explode in the air before they ever reach the ground. As they travel through the air at a velocity of 15-20 kilometers per second, they experience huge pressure forces due to the enormous air resistance felt at this high speed. These pressure forces cause the asteroid to explode violently. When asteroids explode in the air in this manner, they are called airbursts. The explosion energy of an airburst is comparable to the energy released by a ground strike.

If a large asteroid, one kilometer in diameter, impacts a large body of water, such as an ocean, the consequences can be just as disastrous as a ground strike. The impact would create waves hundreds of feet high which can flood and devastate coastal communities all around the world.

There are scientists currently monitoring outer space for asteroids that threaten to impact the earth. Fortunately, the vast majority do not. But occasionally, some do. On February 15, 2013, an asteroid 20 meters in size entered the earth's atmosphere over Russia, at a speed of about 20 kilometers per second. It exploded about 30 kilometers above the earth in a massive airburst explosion estimated to be about 20-30 times more powerful than that of the atomic bomb dropped on Hiroshima. It created a very bright flash, brighter than the sun, and generated a powerful shock wave that blew out many windows. 1500 people were injured. The asteroid was estimated to weigh over 10,000 tonnes.

Here is a video of the asteroid as it explodes.


This is the largest known natural object to have entered earth's atmosphere since the 1908 Tunguska event which flattened 2000 square kilometers of remote forest in Siberia. Its blast energy was about 1000 times greater than that of the atomic bomb dropped on Hiroshima.

Early warning of an asteroid impact is crucial to saving as many lives as possible. It is currently far too easy for a planet-killing asteroid to be undetected until it's too late. Attempts are currently being made to ramp up the monitoring efforts for improved early warning, since this will save as many lives as possible.

In 2008, a successful early detection was made. The asteroid, called 2008 TC3, was 4.1 meters in diameter and weighed 80 tonnes. It entered earth's atmosphere on October 7, 2008 and exploded as an airburst at an altitude of about 37 kilometers above the Nubian Desert in Sudan.

More ambitious plans involve preventing deadly asteroids, which are on a collision course with earth, from hitting the earth. This would involve deflecting the path of the asteroid somehow, perhaps by sending out a rocket to collide with it, and knock it off course. Other more elaborate strategies are possible, such as using focused solar energy to vaporize material from the asteroid surface, creating a small thrust, which, over the course of months and years, can deflect the asteroid trajectory sufficiently to prevent it from colliding with earth. This however, requires that knowledge of its impending collision be known well ahead of time.


Size and Mass of a typical &ldquosmall&rdquo asteroid that impacts the Earth? - Astronomy

Mass density:
Target Cohesion (lab scale):
Assumed Cohesion at this crater scale:
Friction Angle:
Porosity (%):


To gravity or asteroid size "Other":


Note that the pressure effects are not known for most cases..

Explosive Weight (Yield)
(equiv TNT weight for Nuclear)
Shape

PiV versus Pi2
plot from:

to:

Density
Nuclear Device Weight
 

Actual Diameter:
and the Energy is:
To Change select "Other":
+ means buried, scaled to tnt radius

To Change Values select "Choose":

(or choose crater diameter below):

Velocity:

From Vertical:

Normal Component:
Plot PiV (type below) versus Pi2 for a range of impactors
from:
to:

(for impacts, can input this and solve for impactor)

Crater Volume
(below original surface)

(The values in the output boxes above now are for the central excavation pit crater, the spall crater is indicated here:)


NASA Will Aim a DART at Target Asteroid in Upcoming Deflection Test

Nudging this asteroid will give valuable clues for surviving a prospective hit.

Telescopes and spacecraft are already watching the skies for potentially hazardous asteroids, but what could be done to actually deflect a dangerous object heading toward Earth?

On May 1, the audience at the 6th International Academy of Astronautics Planetary Defense Conference heard more than a dozen presentations related to an upcoming test to nudge an asteroid, and the potential follow-up mission that would view the results up close.

The upcoming mission, called the Double Asteroid Redirection Test (DART), will send a spacecraft to crash into an object typical of the size of those asteroids that could pose a threat to Earth. According to NASA, almost one-sixth of the known near-Earth asteroids (NEA) are multiple-body or binary systems, and DART will travel to one such system to perform its mission.

The overall goal of the mission &mdash which will conduct its crash test in about two years &mdash is to gauge what future tools can successfully deflect the orbit of a potentially hazardous asteroid. The mission is led by the Johns Hopkins University Applied Physics Laboratory (JHU/APL) and is managed by the Planetary Missions Program Office at Marshall Space Flight Center for NASA's Planetary Defense Coordination Office.

DART will travel to the binary asteroid system 65803 Didymos and will slam into the smaller of the two objects, also known as "Didymoon'' or Didymos B. The two rocks may receive another earthly visitor after DART, too. The European Space Agency is proposing a mission called Hera, which would explore Didymos and, alongside the first two European cubesats to travel into deep space, learn about the aftermath of the DART impact.

Didymos is about 2,540 feet (775 meters) wide, and Didymoon measures 540 feet (165 m) across.

The mission's launch window is now slated to open in July 2021, according to DART Project Manager Cheryl Reed. She also said on May 1 that current estimates suggest the spacecraft will carry a mass of 1,224 lbs. (555 kilograms) and will achieve a closing speed of 14,900 mph (24,000 km/h) before smashing into Didymoon in 2022.

The spacecraft will use the "kinetic impactor" technique to strike Didymoon and change the asteroid's motion. (The probe will not employ any explosives.)

An element to this collision that several researchers touched on at the conference was how much material ejected from the asteroid after the spacecraft hit would help boost deflection &mdash the momentum enhancement factor, which is known as beta. Research teams are working on 2D and 3D models to better understand how Didymoon's composition, surface material or DART's angle of impact, for example, would affect deflection.

The Hera mission will receive a final full funding decision in November 2019. If it does get the green light, Hera and its two cubesats, APEX and Juventas, will make a series of measurements, observing the shape of DART's impact crater, Didymoon's mass, the asteroid's density and porosity, and more.


Earth-crossing asteroid

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Earth-crossing asteroid, asteroid whose path around the Sun crosses Earth’s orbit. Two groups of such asteroids—Aten and Apollo asteroids—are distinguished by the size of their orbits and how closely they approach the Sun. The Atens and Apollos cross Earth’s orbit on an almost continuous basis. Astronomers have mounted searches for objects that closely approach Earth, partly to determine whether they may collide with the planet, since early detection might make it possible to avert a catastrophe. It is currently estimated that there are about 1,000 Earth-crossing asteroids larger than 1 km (0.6 mile). Asteroids in inner solar system planet-crossing orbits move back and forth among the various kinds of such orbits before eventually colliding with a planet or being ejected from the solar system. Impacts of 1-km-size asteroids are believed to occur a few times every million years. Such a collision would deliver the explosive force of several hydrogen bombs, possibly resulting in global climate disturbances or huge tidal waves. The impact of an object about 10 km (6 miles) in diameter is thought to have caused a massive extinction of species, including the dinosaurs, at the end of the Cretaceous Period (66 million years ago).

This article was most recently revised and updated by Erik Gregersen, Senior Editor.


1 Answer 1

Notably, the body that created the fireball was initially only

4 meters in diameter with a mass of 200,000 kg prior to atmospheric entry, traveling around 16 km/s (Brown et al. 2000). This is substantially smaller than the object that caused the airburst over Chelyabinsk (see Popova et al. 2015), which I'll discuss later. This mass was reduced prior to the explosion, as much of it was ablated as it traveled through the atmosphere.

I'm extremely skeptical of the claim because we have evidence that much of the area's telecommunications equipment functioned perfectly normally in the aftermath of the blast. This Master's paper relates accounts of the Tagish Lake event from locals in the area, including northern British Columbia and much of the Yukon Territory. It appears that immediately after the explosion, the radio station in Whitehorse was broadcasting as normal to a wide area:

The phone calls started immediately. With the contrail still bright, eyewitnesses called friends they called the authorities they called scientists they called the media. Authorities and scientists and media all called each other, trying to nail down what had just happened. The phone lines at the local radio station of the Canadian Broadcasting Corporation filled with witnesses anxious to share their stories, and it was up to Peter Novak's calm baritone to mediate discussion on his daily program, The Valley Voice.

Whitehorse is claimed to have been near the blast (well, tens of kilometers below it, vertically). While landlines and individual cell phones would not necessarily be affected by an EMP, cell towers and other infrastructure might be - rendering communications difficult. This presumably includes equipment needed to broadcast the aforementioned radio show. It would be a bit surprising if there was no effect on telecommunications nearby if the electrical grid had severe problems - and yet folks seem to have been able to communicate just fine, including in Whitehorse.

It's not implausible that a meteor could cause electromagnetic activity in the atmosphere, but there's a significant difference between electromagnetic activity and an electromagnetic burst. There are a couple known cases of electrophonic bursters (which have an unfortunately similar name), meteors which were accompanied by pops and clicks. It has been proposed (Beech & Foschini 1999) that the sounds are caused by shock waves propagating through the plasma caused by the ablation of the meteor as it travels through the atmosphere, causing pulses in the electric field of the plasma and in turn causing sounds, which can propagate through the atmosphere.

These pulses are distinct from EMPs in the typical sense, of course. Remember the Chelyabinsk burst I mentioned? It did cause electrophonic sounds, but it did not cause an EMP. It did affect telecommunications, but through shock waves, not an electromagnetic pulse (Popova et al. 2013):

Electrophonic sounds were heard (SM Sect. 1.6), but there was no evidence of an Electromagnetic Pulse (EMP) under the track in neighboring Emanzhelinka. Due to shock wave induced vibrations, electricity and cell phone connectivity was briefly halted in the Kunashaksky district at the far northern end of the damage area.

The shock wave from the explosion did damage - not any sort of electromagnetic activity. Moreover, the Chelyabinsk object was substantially more massive than the body that impacted at Tagish Lake. The above paper estimates a mass of about 13,000,000 kg and a diameter of around 20 meters, traveling at 19 km/s.