Asteroid Apophis

[Zatnikitelman]

http://www.gateworld.net/news/2008/09/apophis_may_yet_destroy_earth.shtml
Sadly, it looks the hype about this thing is up again. On behalf of Stargaters everywhere, I apologize.
Have we been able to make any orbital refinements for the 2029 pass which would refine the predictions for the 2036 pass? I really don't think it'll hit us however.

 

[astrosammy]

Apophis may yet destroy Earth

I ask me why everyone thinks that a 0.27 km asteroid will destroy earth...

Maybe because of all this youtube videos?

But it will be a great thing to watch 2029.

 

[RisingFury]

To my knowledge this will fly very close. But I don't know if it will be observable with naked eyes.

I remember the 1995 Haley-bopp comet... I was 9 years old and fascinated by it...

 

[astrosammy]

I think it can even be visible with the naked eye. There must be a way to calculate this.

Moon is 384000 km away and it's diameter 3500 km.
Apophis will fly by at 10000 km or even lower. It's diameter is 0.27 km.

Moon: 3500 / 384000 = 0.0091
0.0091 / 0.0091 = 1
1 * 100 = 100

Apophis: 0.27 / 10000 = 0.000027
0.000027 / 0.0091 = 0.00297
0.00297 * 100 = 0.3

100 / 0.3 = 333

So if I've done that right it should be visible 333 times smaller than moon.
Seems to be enough to be visible at night with the naked eye in rural areas, and in urban areas with binoculars (if the magntude is high enough).

 

[Pilot7893]

I heard on the science channel its pass will take it closer than most weather satalites

 

[Urwumpe]

I heard on the science channel its pass will take it closer than most weather satalites

Well, only about 40,000 km distance actually according to the latest data.

 

[steph]

Don't worry...it'll just pass through earth, according to my literature teacher:rofl:

 

[thomasantony]

I think it can even be visible with the naked eye. There must be a way to calculate this.

Moon is 384000 km away and it's diameter 3500 km.
Apophis will fly by at 10000 km or even lower. It's diameter is 0.27 km.

Moon: 3500 / 384000 = 0.0091
0.0091 / 0.0091 = 1
1 * 100 = 100

Apophis: 0.27 / 10000 = 0.000027
0.000027 / 0.0091 = 0.00297
0.00297 * 100 = 0.3

100 / 0.3 = 333

So if I've done that right it should be visible 333 times smaller than moon.
Seems to be enough to be visible at night with the naked eye in rural areas, and in urban areas with binoculars (if the magntude is high enough).

Just the size isn't enough. You also have to see if its albedo is light enough to reflect enough light from the Sun.

~

 

[RisingFury]

Just the size isn't enough. You also have to see if its albedo is light enough to reflect enough light from the Sun.

~

And not just that.

You have to take several factors into account:
- angle of the surface
- dust around the comet
- position of the comet relative to Earth and the Sun.
- size
- distance
- albedo



Depending on where it will fly, there's a chance we won't ever see it because the part facing us may never be lit by the Sun when the thing is close enough to see it.

This is a relatively small rock. The Hale-Bopp was what? 100 km?
One paper even claims (on theoretical ground) that it's a binary nucleus with 70 km and 30 km nuclei... which would explain it's dust emissions.