# Why use "the" in "than the 3.5bn years ago"?

Why has the been used before 3.5bn in the sentence below? Doesn't the sentence make sense without the the?

Researchers hope rocks collected here will confirm that volcanic activity on the Moon continued until far more recently than the 3.5bn years ago that is the estimate derived from studies of currently available samples.

• He looks taller than the five-foot-nine recorded on his medical card. I personally don't find that syntactically acceptable without the article. But interestingly, that article becomes simply optional if I include the [conjunction?] as, as in He looks taller than [the] five-foot-nine as recorded on his medical card. I can't explain that, though. Nov 24, 2020 at 12:36
• @FumbleFingers I’ve no reference for this, but intuitively I’d say that in the five-foot-nine recorded on his medical card, the the refers to the entire phrase five-foot-nine recorded on his medical card. When the as is added, the phrase is spliced and as recorded on his medical card becomes ancillary to the main phrase He looks taller than five-foot-nine. Nov 25, 2020 at 9:08
• Compare: "the amount of time that is the estimate derived from studies of current available samples, which is 3.5bn years" Nov 25, 2020 at 16:07
• Another more everyday example: “Here’s the five pounds I owe you.”
– PLL
Nov 26, 2020 at 21:56

The reason for "the" is that this refers to a particular 3.5 bn year limit, i.e. the specific one that was mentioned in the previous research.

You may object that there aren't distinct 3.5 bn years ago eras - there can only be one. Logically that is true but sometimes usage overrides logic.

So we could say

1. 3.5 billion years ago, there was volcanic activity on the Moon.

2. 3.5 billion years ago, the first signs of life appeared on Earth.

These are independent statements so we could talk about "the 3.5 billion years ago that there was volcanic activity" and "the 3.5 billion years ago that there was life on Earth".

The reason we can refer to them in this way might be because they are both estimates and one might be a much more accurate estimate than the other, so they are in some way distinct.

• In this case, "same" is likely elided: "The [same] 3.4 bn years ago that"... Nov 25, 2020 at 23:11
• On another route, "the" is specifying a particular period of time, and substituting that into OP's sentence: "... far more recently than the [period] that is the estimate..." shows the grammatical necessity. Nov 26, 2020 at 19:23
• I would say it's best understood as an ellipsis. "Than the [figure of] 3.5 bn ya that is the estimate derived..." Similarly, "Than the [height of] 5-foot-9 recorded on his driver's licence..." Nov 27, 2020 at 19:38

This is so because "3.5 bn years" is determined by the that-clause (that is the estimate derived…) and that it is a unique possibility.

• This is not the bundle (that) they showed to you. (unique)
• This is not a bundle (that) they showed to you. (not unique)

The determination can result from other circumstances.

• This is during the first hour on the job. It is for the second hour that you need to use new tools.

In my opinion, Jack Rowntree does detect a problem in the formulation of the proposed sentence, and if I failed to give sufficient thought to it as I read the sentence, I feel now that his remarks make it stand out enough to address it, which I wouldn't have done had I not disagreed to a certain extent with him.

This number of years is a means to define a date; a point in time is what we have to specify since the key word is "until"; we do that not by means of a date since for such times way back in the geological times and still further back, dates are rather meaningless, unless it would be rather that there is no established usage; instead it is done by means of a span of time with the convention that the inferior limit of that span is the point or date referred to; however, in order to establish a correspondence in time for that inferior limit the superior limit must be fixed. You can fix it in several ways, by choosing a reference point, an event, a period if an approximate date is sufficient. Here, this is accomplished by a reference to the present in general (which is again an approximation but sufficiently good since even several decades do not matter in this question); the term to fix that reference is "ago". As Jack Rowntree notices the formulation is unusual or at least it doesn't have the feel of proper syntax. This is correct in my opinion since the term in the comparison is not a simple term but "3.5 bn years ago"; as "the" does not bear upon "ago" there is not a well defined term for the comparison; this is highlighted in Jack Rowntree's answer. As he shows, an apparent solution is to suppress "ago".

• Researchers hope rocks collected here will confirm that volcanic activity on the Moon continued until far more recently than the 3.5bn years that is the estimate derived from studies of currently available samples.

However, that does not define a date but a span of time and this is not proper. If keeping the article, the only way out towards normal syntax is in an addition of terms.

• Researchers hope rocks collected here will confirm that volcanic activity on the Moon continued until far more recently than the point 3.5bn years ago, that is the estimate derived from studies of currently available samples.

There is also, according to Jack Rowntree the possibility of doing away with the article and I agree entirely with that.

• Researchers hope rocks collected here will confirm that volcanic activity on the Moon continued until far more recently than 3.5bn years ago, (that/which) is the estimate derived from studies of currently available samples.

Previous studies suggested that volcanic activity on The Moon ended about 3.5bn years ago. The analysis of recently collected rocks, however, have lead scientists to suspect volcanic activity ended after the accepted 3.5hn years.

"the" refers to the previous estimate, 3.5bn years.

• Yes, +1, Although I have answered slightly differently, I think we are saying much the same thing. Nov 24, 2020 at 12:35

The phrases "3.5bn years ago" and "the estimate derived from studies of currently available samples" are in apposition to each other - both refer to the same thing.

You can leave out the first "the" by separating the two phrases with a comma:

... until far more recently than 3.5bn years ago, the estimate derived from studies of currently available samples.

Or you can make the second phrase into a relative clause explaining the meaning of "3.5bn years ago", replacing "that" with "which":

...until far more recently than 3.5bn years ago, which is the estimate derived from studies of currently available samples.

IMO the original quotation would be acceptable and easily understood in spoken English, but the grammar seems a bit careless for written English. It seems to me as if a speaker was going to say

...until far more recently than the estimate derived from studies of currently available samples.

but then added the extra information about the numerical value of the estimate (3.5bn years) in the "wrong place" in the complete sentence.

If someone asks me how many bananas I have, and I say "I think I have seven", and then they ask me how many oranges I have, and I say "I think I have seven", the number "seven" has appeared twice, but it's not the same seven. They refer to different things and might be obtained from different sources and have different levels of certainty. If you ask me "Do you have the same number of bananas as oranges?", I might say "I don't think so": even though my estimates for them are the same, I might be unsure enough of each that I think there's a good chance that they aren't the same. And I can talk about them separately. For instance, I can say "The first seven comes from knowing that I bought ten yesterday, and my roommate has a habit of eating three bananas each day. The second seven comes from the fact that I picked some oranges and they filled up my bag, and my bag holds about seven oranges." This is a perfectly coherent statement. So numbers can act like nouns in this sense, and we can talk about particular ones, and they can take definite articles when we're referring back to previously specified ones.

• The necessity of the uniqueness is not stated in this answer but the example implicitly shows that: there is only one "seven" that can be the first.
– LPH
Nov 25, 2020 at 6:07
• This answer is slightly misleading though in its explanation about the numeral being treated as a noun. In the OP's sentence "the" is not a determiner of "3.5 bn" but a determiner of "years".
– LPH
Nov 25, 2020 at 6:28
• If you've estimated 7 oranges and 7 bananas then I think it would be more natural to answer the question about whether you have the same number of each with "I think so". If you're fairly sure the number is different it would have made more sense to make the estimates less precise. Nov 25, 2020 at 9:15

This feels wrong to me.

The below feels OK:

than the 3.5bn years [no ago] that is the estimate derived from studies of currently available samples.

As does:

than [no the] 3.5bn years ago, (that/which) is the estimate derived from studies of currently available samples.

Specifically, I would say `*the* 3.5bn years ago` basically feels wrong in the original. The definite article brings focus to the years themselves, ago/in the past, rather than the idea of a stated estimate. The next clause still uses `is` to refer to the concept of said estimate, but the previous definite article has primed us to think about years plural. I'm sure I've never seen that phrasing written or spoken. I would advise against using it.

• I agree with your correction of the sentence, essentially; you can read what I think of it in the addition to my answer.
– LPH
Nov 26, 2020 at 10:45