Scientists have long speculated

English as a Second Language English Vocabulary, Grammar and Idioms
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Because of the proximity and likeness of Mars to Earth, Scientists have long speculated about the possibility of life of Mars.

What does the bold part mean?

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***** NOT A TEACHER *****

Hello, S.C.:

Please excuse me, but I do not understand why that sentence confuses you.

I am NOT a good reader, but that sentence seems very easy to understand (or maybe I am wrong).

“Speculate” – says my dictionary – is “to form a theory without firm evidence.”

So your sentence (I think) simply means something like:

Scientists have long guessed – without any real evidence – that there is life on Mars.

The reason for this speculation (guessing) is that Mars is so close to Earth and that Mars is “like” the Earth in many ways. So …

I think that “speculate” is often a “big” word for “guess”:

Mona and James got a divorce. Nobody was really surprised. People had long speculated that their marriage was in trouble.

James

3

Yes! James. I had to narrate what of the sentence bother me. Sorry.

I actually feel difficult with “long” there. What is long speculation mean there. Is it mean that Scientist has been speculating since long time ago?

4

***** NOT A TEACHER *****

Hello, S.C.:

I believe that you are 100% correct.

“Scientists have speculated FOR A LONG TIME about the possibility of life on Mars.”

James

P.S. Nothing to be sorry about. If anyone should be sorry, it is I. I did not express myself gently enough. Sorry!