1. ## tantalizingly and off

Hi,

Does "tantalizingly" in this case mean, pretty close ?

And what does "off" mean in this context? I already looked it up in the dictionary, but it seems nothing helpful for me!

This Professor is talking about how the asteroid belt was discovered.

Professor: Yes, I divided all those numbers by 10 by putting in a decimal point. Now I'm gonna write the names of the planets under the numbers. Mercury...Venus...Earth,,, So, what do the numbers mean?

Student: Is it the distance of the planets from the sun?

Professor: Right, in astronomical units-not perfect, but tantalizingly close. The value for Mars is off by...6 or 7 percent or so. It's...but it's within 10 percent of the average distance to Mars from the Sun. But I kind of have to skip the one after Mars for now. ...

2. ## Re: tantalizingly and off

tantalizingly close - close; very close, but not quite there; very close but still off the mark; almost perfect--almost
off - in error. If the actual number is 100 but what you get us 97 then you are off by 3. (The word "off" is also used to mean "not quite right".)

3. ## Re: tantalizingly and off

Originally Posted by RonBee
tantalizingly close - close; very close, but not quite there; very close but still off the mark; almost perfect--almost
off - in error. If the actual number is 100 but what you get us 97 then you are off by 3. (The word "off" is also used to mean "not quite right".)

Hi, RonBee,

I am pretty grateful for your help. Thank you.

And, here I hope you could take a look for me. Then the Professor says: This pattern is known as Bode's Law, which is not a scientific law, not in the sense of predicting gravitation mathematically or something, but it's attempting a pattern in the spacing of the planets, and it was noticed by Bode hundreds of years go. Well, you can imagine that there was some interest in why the 2.8 spot in the pattern was skipped, and...but there was anything obvious there, in the early telescpoes. ...

My question is what does "spot" refer to here? It means 2.8 percent place? I can not get this one.

4. ## Re: tantalizingly and off

Originally Posted by XINLAI-UE
Hi, RonBee,

I am pretty grateful for your help. Thank you.
Well, you can imagine that there was some interest in why the 2.8 spot in the pattern was skipped, and...but there was anything obvious there, in the early telescpoes. ...
My question is what does "spot" refer to here? It means 2.8 percent place? I can not get this one.

First, "pretty grateful" means "grateful, but not excessively". It's probably not the best way to use "pretty".
But to your question: you'd probably have to be an astronomer to know what a "2.8 spot" was. I would assume that there is a table or chart, measured from one to ten, say. If most of the spots were around 8 on the chart, the 2.8 spot might be an artifact/false positive/outlier.
The spot could either be a physical spot (like a point on a line), or it could be a metaphorical spot (such as the 2.8 level/place on the chart where a physical spot could be). Then the (physical) spot could be at the 2.8 spot (place) on the chart.

5. ## Re: tantalizingly and off

XINLAI-UE, I read your question, and I read Raymott's response to it. My response would have been something like, "I have no idea." Raymott, however, came up with a much more clever way of saying "I don't know".

6. ## Re: tantalizingly and off

Originally Posted by RonBee
XINLAI-UE, I read your question, and I read Raymott's response to it. My response would have been something like, "I have no idea." Raymott, however, came up with a much more clever way of saying "I don't know".

Well, at least I had a go.

7. ## Re: tantalizingly and off

It has to do with Bode's Law. This is from an email I received:
Bode's Law predicts that the distances of the planets from the Sun, should go up in the following sequence (measured in Astronomical units - AU)
0.4 - 0.7 - 1.0 - 1.6 - 2.8 - 5.2 - 10.0 - 19.6 - 38.8
At roughly those distances, there are.
0.4 - Mercury - at 0.4au
0.7 - Venus - at 0.7au
1.0 - Earth - at 1.0au
1.6 - Mars - at 1.5au
2.8
5.2 - Jupiter - at 5.2au
10.0 - Saturn - at 9.5au
19.6 - Uranus - at 19.2au

As you can see, the planets actually do occupy positions at (or very near to) those predicted by Bode's Law.
Also - you'll see that there's nothing major at 2.8au (the 2.8 'spot' in the sequence).
Or at least that's what we used to think.

We have since discovered the asteroid belt, which averages at around 2.8au - including the orbit of Ceres (discovered 1801), which is by far the most massive asteroid.
That explains the 2.8 spot.

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