# Credibility

I was loving every sentence of this article until I came to this one:

Though the hole’s depth is impressive, it’s a small fraction of the distance to the center of the Earth, which is estimated to be nearly 4,000 miles deep.

They lost all credibility with that one sentence.

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## 18 thoughts on “Credibility”

We know the circumference of the earth and the elevation of all points on the surface with great precision. Hence we know the distance to the center of the earth from any point on the surface with great precision.

• Well, what is the meaning of “estimated”? Dictionary says it’s “to give or form a general idea about the value, size, or cost of (something).”

Seems to me, “about” and “estimated” are the same thing. ????

• “About” is an approximation, rounding up/down to make manageable numbers.
“Estimated” is a guess; it carries an inherent uncertainty.

There’s a difference. We know how large the Earth is; there’s no need to guess and there’s no uncertainty.

• No. An estimate is not the same thing as knowing for sure. If you know for sure that it is, let’s say 4015.2567 miles, and you say it’s “about 4000 miles” because 4000 is close enough to the actual, known number for the purposes of the discussion, that’s far different from saying it’s “estimated to be” about 4000 miles. “Estimate” is used when we’re not certain– It’s closer to the word “guess”.

Same for the average distance to the moon, or the mileage you get with your car. We know exactly, or can fairly easily come up with the exact number or set of numbers, but “about 284 thousand miles”, or “about 20 miles per gallon in level, straight driving with no wind and only the driver as cargo”, is close enough in most cases that it’s not important. Neither is an estimate, which would be based on indirect measurement plus some reasonable or at least defensible assumptions.

• “Seems to me, “about” and “estimated” are the same thing. ????”

That just might give a hint as to why you write some of the other things you write: a failure to understand the meaning of words. Especially given the context in which you wrote it; note the italicized word in Joe’s comment.

• Estimated and about are both approximations. Taking Lyle’s example above (gas mileage), auto companies often give “estimated miles per gallon.” That’s not considered to be a WAG.

• Looking at the dictionary again, “about” means “almost or nearly.” Considering the writer wrote “nearly 4,000 miles” — there’s your “about.” It’s that “nearly.”

• No, Ubu — “to estimate” is a WAY to calculate an approximate figure from imprecise data, “an estimate” is the result of that calculation approximation. It _can_be_ more than a “WAG”, but it ALWAYS is an educated guess. It IS NOT the same as using an approximate value for a precise figure.

Car companies use estimated MPG because they cannot know YOUR driving habits and conditions, which dramatically affect actual MPG. (My ex-wife and I got MPGs in the same car that varied by approximately 10%, because I was more used to driving in NoVA traffic and was more aggressive on acceleration.)

However, when I do the math on MY car and calculate the mileage for a particular tank of gas (or even an average MPG for many tanks of gas), my answer is not an estimate. If I calculate it as, say 24.37 MPG, I would call it “about 24 MPG” – I’m using an imprecise approximation of an exact figure.

“Based on what I see and hear right now, I estimate the cost of repairs on your car will be about \$1900.” Or “the estimated cost of your repairs is \$1900.”

Once the car is fixed, and the final bill comes out as \$1975.96, you’d probably say it cost ABOUT \$2000. But that isn’t an estimate. . .

Words mean stuff – and estimate IS a technical word. people DO use it incorrectly all teh time, just as they misuse other words frequently.

2. That is an interesting article. I wonder how much drilling has been done to test the theory of plate tectonics?

• Quite a bit for deep core samples. However, the magnetic shifts in oceanic crustal materal (that can be mapped without drilling), AND THE FACT THAT WE CAN NOW DIRECTLY MEASURE CONTINENTAL DRIFT pretty much make it about as validated a theory as you’re likely to find.

3. The red flag I see is the writer’s idea that the intention had something to do with trying to drill all the way to the center of the earth. The wildest dream of a borehole project like that would be to make it all the way to the upper mantle, which may also be impossible, but not nearly as ridiculous as imagining a borehole all the way to the center. This seems to me to be a more profound misunderstanding than being vague on the geometry.

• Very good point.

At the time I was reading that particular portion I was thinking in terms of boring through the crust. But the words said some different. It didn’t really sink in they really meant “center” until they said 4000 miles and I got distracted by the word “estimate”.

4. sirs:

i was taught that the earth’s diameter was roughly 8,000 miles, depending on some localized differences/flucuations in distance caused by gravitational effects from the moon.

the radius would therefore be 1/2 of the roughly 8,000 mile diameter.

i think the writer can be forgiven the use of the word “estimate,” because in a very hyper technical sense, it may not be exactly 4,000 miles to the center of the earth depending upon the location of the bore hole.

and, yes, the writer apparently doesn’t know that the inner core of the earth is not solid, e.g., is it fluid, and may not even be more at the same rotational velocity as the mantle … indeed, some speculate that the inner core derives some of its heat from nuclear activity. and, the earth’s magnetic field may be derived from this movement, so of like a very big “generator.” so, drilling to the center of the earth is a dubious proposition, given our current understanding of what is there.

still in all, an interesting article.

john jay

• We just have to wait till we have to restart the core’s rotation with nukes!

(Yes, I’m making a reference to the astonishingly bad movie ‘The Core’. Did you expect otherwise?)

By the way, Joe, I’m still seeing those fracking 503 errors now and again. Did you piss someone off?

5. Considering that the surface of the planet is not a smooth sphere, and is slightly flattened at the poles, there is some uncertainty in how deep you would have to drill due to the lack of uniformity. 400 feet below sea level to 28,000 feet above sea level is less than six miles of variation, before you take the “equatorial bulge” into consideration.

So, for that particular site in question the word “estimate” is correct if you don’t know the exact distance from the surface to the center of the Earth. However, as written the word “about” would be more appropriate unless the author was speaking specifically about that bore hole.