"Deep Impact" July 4th reminder

[Martin]

http://science.nasa.gov/headlines/y2005/28jun_deepimpact.htm?list45222

 

"The target: a 10-mile wide comet named Tempel 1.

 

...Deep Impact is going to shoot an 820-pound projectile into the rocky, icy nucleus of Comet Tempel 1. The 23,000 mph collision will form a big crater, and Deep impact will observe the stages of its development, how deep it gets and how wide it becomes. Researchers expect a plume of gas and dust to spray out of the crater..."

 

the comet will be near the bright star Spica in the constellation Virgo

 

 

here is a star map for 11PM Pacific Daylight Time on July 3, when virgo will be near setting in the west

http://science.nasa.gov/headlines/y2005/images/deepimpact/skymap_north.gif

 

need a telescope to see the impact event, I think. people on the west coast.

it will be July 4 "independence day" on the east coast but they wont be able to see anything

[Spyman]

need a telescope to see the impact event, I think.

They will (hopefully) release a lot of good images from Hubble and Spitzer space telescopes.

(So there is no need to rush and buy a telescope.)

 

With wordings like "Cosmical Fireworks" and the date 4 July, I guess NASA tries to be more popular ...

(It's still a very scientific mission and not just a commercial event.)

NASA has billed the event as one that can be seen from backyards on Earth. The comet may temporarily brighten enough to be just barely visible to the naked eye' date=' astronomers have said.

 

Based on what he knows of Tempel 1, however, Feldman is not optimistic that the comet will brighten enough to be seen without optical aids. "I wouldn't bet on it," he told SPACE.com.

 

And given the comet's characteristics seen so far, even making it visible through binoculars will require that Deep Impact hit a sweet spot. Thing is, nobody knows where that sweet spot might be or whether the comet is more vulnerable in one location than another.

 

"In the most optimistic case, someone with a pair of binoculars might be able to see it," Feldman said.

 

Expert skywatchers point out that spotting any marginally visible comet can be a challenging task that requires some practice or good advice, the right equipment, and a good sky map.[/quote']

It is possible that the change will be so small you can't see it with anything less than a four-meter telescope. It could be much more than that, it could be that you could see the change with binoculars. You just have to be aware of the uncertainty.

When Deep Impact crashes into Comet Tempel 1' date=' the size of its crater remains will depend on the comet's structure and density. Size estimates from mission scientists describe the crater as ranging from a meager 10 meters to the size of the Rose Bowl football stadium in Pasadena, California.[/quote']

My personal estimate (for the crater) is at the large end of a large-size football stadium' date=' perhaps 150 meters in diameter. It could be larger.[/quote']

Depending on the composition' date=' the result could range from putting a hole all the way through it to not quite bouncing off.[/quote']

We’re sending a bug onto the windshield of a train.

The bottom line is that we have an object the size of a washing machine colliding with a comet the size of Manhattan Island.

http://www.space.com/deepimpact/

[Martin]

They will (hopefully) release a lot of good images from Hubble and Spitzer space telescopes.

(So there is no need to rush and buy a telescope.)

 

With wordings like "Cosmical Fireworks" and the date 4 July' date=' I guess NASA tries to be more popular ...

(It's still a very scientific mission and not just a commercial event.)http://www.space.com/deepimpact/[/quote']

 

Hi Spyman. I calculated the energy release to be

around 20 GJ (sort of like maybe 5 ton of TNT?)

 

maybe you could check. I dont have equivalents handy

 

can you find metric data?

 

the news item here says 820 pounds going 23,000 mph which I translate to be 370 kilogram going 10.3 kilometer per second.

 

so I get kinetic energy is 2E10 joule, or 20 gigajoule. let me know if you see where I made some careless mistake

 

I forget the conversion to conventional tons of TNT but I think it is on the order of a few tons of TNT.

[Martin]

Hey Spyman, check this out

http://arxiv.org/abs/astro-ph/0506721

 

it is a technically solid article about deep impact

what the expectations are

 

in fact my guess that they meant 370 kilograms was right

[Spyman]

Hi Spyman. I calculated the energy release to be

around 20 GJ (sort of like maybe 5 ton of TNT?)

Hi Martin' date=' good estimate !

 

Whether it's 4.5 or 5 tons of TNT it's still a very large firecracker !

 

can you find metric data?

I found this:

The 770-pound (350-kilogram) probe will hit the comet at 22,300 miles (35, 885 kilometers) per hour and penetrate 16 to 32 feet (5 to 10 meters).

The impactor delivers 18 Gigajoules (that's 4.5 tons of TNT) of kinetic energy to excavate the crater.

http://www.space.com/missionlaunches/missions/deep_impact_010502.html

(In one of the links, in the first link I provided.)

[Molotov]

The impact was a success. Looks like we will be getting tons of good images and data from this.

[luc]

 

The impactor socked hard

[Martin]

luc, that is a beautiful photograph.

 

I assume you watched the movie.

YT mentioned it.

In case somebody did not see the movie I will get the link and put it here

 

http://www.nasa.gov/mov/121493main_Impactor%20POV%20to%20crash.mov

 

this is the video taken by the camera in the impactor as it approached the comet. it takes a few minutes to download, with my slow connection