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Well, the summit of Chimborazo in Ecuador is the furthest point on the Earth's surface from its centre, but I don't know what point lies diametrically opposite.

EDIT: Appears to be here. No idea how far that is above sea level though.

GuyBarry wrote: ↑26 Nov 2019, 16:14 Well, the summit of Chimborazo in Ecuador is the furthest point on the Earth's surface from its centre, but I don't know what point lies diametrically opposite.

The opposite point is just on the northern edge of the island of Sumatra, not far south of Kuala Lumpar.

You might find this map useful - https://www.freemaptools.com/tunnel-to- ... -earth.htm

Thanks. That may or may not be the correct answer to the question though - how far is it above sea level?

GuyBarry wrote: ↑26 Nov 2019, 16:31 Thanks. That may or may not be the correct answer to the question though - how far is it above sea level?

What, the very edge of an island in the sea? Not much, I'd say ...

Right, that's probably not the answer then!

There aren't many parts of the world where it can be - only 4.4% of the Earth's surface is land which is antipodal to other land (coloured orange on this map - the overlap between the blue and yellow areas). It's got to be near the Equator, so that limits it still further.

I'm not sure I even understand the question. What exactly is its definition of "planet Earth"?

The way I'm interpreting it is this: find two points on the landmass of the Earth such that the straight line between them through the centre of the Earth is as long as possible.

So I'm hoping to find two mountain ranges that are antipodal (diametrically opposed), so that the line joins up two fairly high points.

I don't think the line necessarily needs to go through the exact centre of the Earth, although it will probably go quite close to the centre. A line between two high mountains that does not pass through the centre might be longer than a line between two lower points that are exactly antipodal.

Looking at that map, it's going to be from the Andes to China, though this forgetting that the sea level to sea level distance through the earth changes depending on your latitude.

GuyBarry wrote: ↑26 Nov 2019, 16:14 Well, the summit of Chimborazo in Ecuador is the furthest point on the Earth's surface from its centre, but I don't know what point lies diametrically opposite.

EDIT: Appears to be here. No idea how far that is above sea level though.

This is the answer I have.

The bulge at the equator dominates, followed by the height of the peaks in the Andes in Ecuador. The island of Sumatra is at the antipodes. Unfortunately, the mountains in the west of Sumatra don't align with the highest peaks in Ecuador.

Taking into account both greatkingrat's and A Challenge's remarks, then, here's a first stab:

Mercedario (31°58′ 45″ S 70°06′ 45″ W, elevation 6720 metres)
Shennong Deng (31° 26' 54'' N, 110° 18' 16'' E, elevation 3105 metres)

Any good?

EDIT: DrainBrain posted the answer while I was making that post - looks as though I was right first time but didn't know it!

I've got one of my own:

What venerable cultural institution unexpectedly began with a racist insult?

GuyBarry wrote: ↑28 Nov 2019, 12:54 I've got one of my own:

What venerable cultural institution unexpectedly began with a racist insult?

The Dambusters (1955)?

Not what I was thinking of, sorry - this was in the 1960s.

To be accurate, it didn't begin with a racist insult but with a report of one.

If it helps, the phrase in question was "stinking ****".