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Posted October 31, 2017 5:01 PM
Pathfinder Tags: challenge question eclipse

This month's Challenge Question: Specs & Techs from GlobalSpec:

A new supersonic passenger airliner is due to take flight next year. A wealthy friend of yours suggests that in 2020 you both charter a flight from Namibia to Argentina to follow the track of the total solar eclipse. What is the problem with your wealthy friend’s suggestion?

Total solar eclipses track eastward, not westward. This is because the Moon moves to the east in its orbit at about 3,400 km/hour and the Earth only rotates to the east at 1,670 km/hr at the equator, so the lunar shadow moves to the east at 3,400 – 1,670 = 1,730 km/hr near the equator. You cannot keep up with the shadow of the eclipse unless you traveled at Mach 1.5.

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Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 20321
#1

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

10/31/2017 5:22 PM

Distance from Argentina to Namibia is 7,801 kilometers. This air travel distance is equal to 4,847 miles.

If you travel with an airplane (which has average speed of 560 mph) from Argentina to Namibia, It takes 8.66 hours to arrive.

The Moon orbits Earth at a speed of 2,288 miles per hour (3,683 kilometers per hour).

The Sun and Moon both appear to “rise” in the east, and “set” in the west. But as you can see in our video of the Moon’s shadow sweeping across the USA, you see that the shadow plainly travels from west to east across the country!

Ooops you're going in the wrong direction....that and he assumes I have enough money to waste in such a manner....

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Guru

Join Date: Apr 2010
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#2

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

10/31/2017 6:09 PM

That's going the wrong direction!

Guru

Join Date: Apr 2010
Location: Trantor
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#3

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/01/2017 8:32 PM

Wrong direction. 99.9% of solar eclipses go west to east, not east to west.

Only rarely a solar eclipse near the N or S pole might go E to W.

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Guru

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Location: NYC until mid 2015, currently NC
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#4

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/01/2017 10:58 PM

Wrong direction, and even if they realized this and flew from Argentina to Namibia, it would be night in Namibia and the eclipse would not be visible.

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Guru

Join Date: Aug 2005
Posts: 4263
#5

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/02/2017 7:55 AM

Wrong direction as others have said; plus even with a "supersonic passenger airliner" you'd be struggling to keep up.

These are the speeds of the shadow during the recent eclipse:

The Boom airliner will have a speed of Mach 2.2: 1577.4 mph

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Guru

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#6

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/02/2017 8:31 AM

The moon's orbital speed is about 2300 mph, west to east, and the shadow moves at essentially the same speed since the moon is much closer to the earth than the sun. The earth's rotational speed at the equator is about 1000 mph, west to east. (At higher latitudes, multiply by the cosine of the latitude.) So the speed of the shadow at the equator is around 2300 - 1000 =1300 mph, west to east, higher at higher latitudes.

In the summertime in either hemisphere, the pole is facing the sun so the shadow could fall on the far side of the pole and would be moving east to west.

Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 20321
#7

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/02/2017 10:50 AM

Yeah, and unless the plane had a sunroof, you'd have to fly sideways to see it....

__________________
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Guru

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Posts: 5279
#8

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/02/2017 1:17 PM

Exactly. These types of solar eclipses can occur, but the configuration doesn't happen very often.

By the way, due to the Moon's slow drift away from the Earth, there will eventually come a time when total solar eclipses will no longer be visible from the Eath's surface. This will occur in a bit over 500 million years.

https://spacemath.gsfc.nasa.gov/earth/4Page28.pdf

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Guru

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Posts: 6147
#9

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/02/2017 1:45 PM

It might be a bit optimistic to think that there will be humans here to lament the loss of total solar eclipses in 500 million years!

Guru

Join Date: Apr 2010
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Posts: 5279
#10

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/02/2017 8:17 PM

I almost added that same thought to my comment!

In the year 2525

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Guru

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#11

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/03/2017 10:25 AM

As all the others have essentially stated, you are planning the trip in the wrong direction, and air line routes also do not travel in so-called straight lines, as they shorten their flight paths by swinging northward or southward, depending on relationship of the flight to the equator.

This would have to be one heck of a fast ride, so maybe this thing if going about Mach 5 could keep up with the penumbra.

It would be best to watch the penumbra from orbit maybe, but you would require an orbit with a matching periodicity to the velocity of the penumbra.

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Guru

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#12

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/03/2017 12:07 PM

This poser does bring to my mind another pair of posers.

Can an orbital optical observation satellite (e.g. Hubbel space telescope) be placed in Earth orbit such that it will be in the umbra for all of this solar eclipse? [I believe this is true with a "fly by" eliptical trajectory but I'm not sure an orbit is possible.]

Is it possible for this satellite to always be in a perpetual solar eclipse? [This one is easy.]

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Guru

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Posts: 4263
#13

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/03/2017 1:35 PM

Turns out that Namibia to Argentina in either direction is a totally random and wrong route to choose for the June 2020 eclipse

From xjubier

Edit: It might be a good idea for December 2020 though

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We are alone in the universe, or, we are not. Either way it's incredible... Adapted from R. Buckminster Fuller/Arthur C. Clarke
Guru

Join Date: Dec 2008
Location: Long Island NY
Posts: 12590
#14

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/03/2017 2:01 PM

Maybe the jet is actually a Tardis.

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"Don't disturb my circles." translation of Archimedes last words
Guru

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 14345
#15

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/03/2017 2:54 PM

No.

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Power-User

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#16

Re: Flying in the Shadow of the Moon: Newsletter Challenge (November 2017)

11/07/2017 11:29 AM

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