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Billion-Ton Comet May Have Missed Earth by a Few Hundred Kilometers in 1883

technologyreview.com

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Re: Billion-Ton Comet May Have Missed Earth by a Few Hundred Kilometers in 1883

#2

Post by dmix »

> They point out that nobody else on the planet seems to have seen this comet passing in front of the Sun, even though the nearest observatories in those days were just a few hundred kilometers away.

This is 1883 and noone else recorded seeing it? Even in all of mexico?

Re: Billion-Ton Comet May Have Missed Earth by a Few Hundred Kilometers in 1883

#3

Post by Gustomaximus »

dmix wrote: post #2

> They point out that nobody else on the planet seems to have seen this comet passing in front of the Sun, even though the nearest observatories in those days were just a few hundred kilometers away. This is 1883 and noone else recorded seeing it? Even in all of mexico?

The do say in the article about no-one seeing it;

"That can be explained using parallax. If the fragments were close to Earth, parallax would have ensured that they would not have been in line with the Sun even for observers nearby. And since Mexico is at the same latitude as the Sahara, northern India and south-east Asia, it's not hard to imagine that nobody else was looking."

Is this realistic? Also would the time of day matter? If the sun was low to the horizon etc.

Re: Billion-Ton Comet May Have Missed Earth by a Few Hundred Kilometers in 1883

#6

Post by temphn »

No photographic evidence. No corresponding accounts. No raw data.

  Bonilla published his account of this event in a French 
  journal called L'Astronomie in 1886. Unable to account for 
  the phenomenon, the editor of the journal suggested, 
  rather incredulously, that it must have been caused by 
  birds, insects or dust passing front of the Bonilla's 
  telescope.
As the saying goes: when you hear hoof-steps, think horses, not zebras.

Re: Billion-Ton Comet May Have Missed Earth by a Few Hundred Kilometers in 1883

#7

Post by Shank »

venus wrote: post #5

> A sobering thought. An even more sobering thought is that even in the present day, if we detected something like that heading our way, there'd be absolutely nothing we could but sit and wait for it to arrive.

This is slightly true, though notably the Torino Scale mentions that once an object is classed at level 5, governments may begin to take action to counteract such a collision before it arrives at earth, if the encounter is set to be less than a decade away.

http://en.wikipedia.org/wiki/Torino_Scale

Edit: NASA's JPL maintains the Sentry Risk Table, which tracks all objects that may impact the Earth, with various data points about said objects.

http://neo.jpl.nasa.gov/risk/

Re: Billion-Ton Comet May Have Missed Earth by a Few Hundred Kilometers in 1883

#8

Post by [deleted] »

Shank wrote: post #7
venus wrote: post #5

> A sobering thought. An even more sobering thought is that even in the present day, if we detected something like that heading our way, there'd be absolutely nothing we could but sit and wait for it to arrive.

This is slightly true, though notably the Torino Scale mentions that once an object is classed at level 5, governments may begin to take action to counteract such a collision before it arrives at earth, if the encounter is set to be less than a decade away. http://en.wikipedia.org/wiki/Torino_Scale Edit: NASA's JPL maintains the Sentry Risk Table, which tracks all objects that may impact the Earth, with various data…

[deleted]

Re: Billion-Ton Comet May Have Missed Earth by a Few Hundred Kilometers in 1883

#10

Post by rorrr »

venus wrote: post #5

> A sobering thought. An even more sobering thought is that even in the present day, if we detected something like that heading our way, there'd be absolutely nothing we could but sit and wait for it to arrive.

That's not true. If we knew for a fact that it would cause global extinction, we would throw everything at it.

We could blow it up with nukes.

We could put a relatively heavy space probe next to it and deflect its course.

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