Friday the 13th, 2029? The odds of impact

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Discussion Overview

The discussion revolves around the potential impact of asteroid 2004 MN4 on Earth, specifically focusing on the evolving odds of impact and the implications of such an event. Participants explore various aspects of asteroid risks, including historical context, comparisons to other dangers, and theoretical approaches to asteroid interception.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants note that the odds of impact have fluctuated, with estimates changing from 1 in 300 to 1 in 45, and then to 1 in 37.
  • Others express concern about the implications of an asteroid impact, referencing the Tunguska event as a point of comparison for potential damage.
  • A participant mentions that current estimates suggest a 97.8 percent chance that the asteroid will miss Earth, which provides some reassurance.
  • There is a discussion about the risks posed by other celestial objects, including extrasolar objects, with some arguing that the threat from solar system objects is greater.
  • Several participants reflect on the historical perception of comets and asteroids as omens of doom, questioning whether this fear is rooted in human experience or simply fear of the unknown.
  • Technical discussions arise regarding the feasibility of landing on or intercepting the asteroid, with varying opinions on the challenges involved, such as delta-v requirements and velocity matching.
  • Some participants humorously compare the risks of asteroid impacts to everyday dangers, such as driving or consuming fast food.

Areas of Agreement / Disagreement

Participants express a mix of concern and humor regarding the asteroid threat, with no clear consensus on the overall risk or the best approach to mitigate it. There are competing views on the significance of the asteroid's potential impact and the feasibility of interception.

Contextual Notes

Participants reference various estimates and updates regarding the asteroid's trajectory and risk, indicating that the situation is dynamic and subject to change. There are unresolved questions about the asteroid's composition and the specific risks posed by other celestial objects.

Who May Find This Useful

This discussion may be of interest to those studying astronomy, planetary defense, or risk assessment related to celestial impacts, as well as individuals curious about the historical and cultural perceptions of asteroids and comets.

  • #31
"how fast will it be passing by?" - in the region 20 -100 000 mph.

"what is this asteroid made of? " - stone or iron or a mixture of the two.

Garth
 
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  • #32
20 mph is not that much...

So in other words we need more precise info before we can truly determine even the feasibility of a landing, let alone the benefits of it.
 
  • #33
I think he meant 20 000 mph, not 20mph.

For that matter, if an asteroid is (as it appears in the link) in a similar orbit around the sun as the earth's, then it must have a very similar orbital velocity, on the order of 67,000 mph (I think).
 
  • #34
rachmaninoff said:
I think he meant 20 000 mph, not 20mph.
Of course!

Garth
 
  • #35
I wonder, Could it be possible for that Asteroid to come so close that it were to suddenly come into orbit around the Earth. Then maybe the possibility of it becoming the 2nd moon of the Earth? How large is this Asteroid?

NVM: I doubt that what I said would happen, from the looks of the moving time diagram given, the 2004 MN4 is orbiting at a pretty good velocity. The Earth's gravitational pull doesn't look strong enough to capture that asteroid. But what do I know, I don't have any numbers ot prove it.
 
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  • #36
Orbital velocity of 2004 MN4

Period of revolution about sun, P = 0.8853 y
Distance from sun at Perihelion, q = 0.7457 AU
Distance from sun at Aphelion, Q = 1.0982 AU
Inclination wrt Ecliptic, i = 3.3334 deg

So it crosses Earth's orbit twice, and the orbit of Venus twice during one of it periods. See my previous post in this thread with a link to the NASA site that shows the orbit of 2004 MN4. (Note - there is no orbital precession, so the simulator is not entirely accurate).

As it nears the Earth's orbit, the velocities are very close, probably on the order of 1 km/s (3600 km/h or 2200 mph) apart. Outside of Earth's orbit, the 2004 MN4 is traveling slightly slower, and as it nears the orbit of Venus, its speed is a little faster than Venus. But what counts is the velocity in the vicinity of the Earth. If it got near enough to the Earth, the Earth's gravity would accelerate it.

The mean Earth orbital velocity is approx. 29.786 km/s (107,229 km/h).

To capture it one would have to decrease the orbital velocity to less than escape velocity from earth, which is about 11.1 km/s (40,200 km/h, or 25,000 mph). Compare this to the moon's orbital velocity of 1.023 km/s.

If anyone wants to worry about something, take a look at all the other NEO's - http://neo.jpl.nasa.gov/orbits/
 
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  • #37
I think if we get hit, it'll be by one we didn't see coming. How long has this asteroid been orbiting the sun? 1000s of years, typically crossing our orbit twice a year?
 

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