That was quite a post, I will start here;
No I don't assume very often. You can be fairly certain that anything I say I have scripture that backs the point or I simply don't say it. The whole Post-Wrath theory is laid out that way. I formed the theory around what I could prove with a multitude of scriptures. Now concerning the cosmic signs they are described two different ways as you say. But they are equal descriptions as we can see from here in Joel.
Well a theory is an assumption is it not? You say that the scriptures you point to prove your theory, yet I am not convinced, so you have failed to prove your theory at least to me anyway. But I don't have a problem with theories and assumptions, as I too share my own theories based on what I believe is empirical evidence found in the scriptures. That is why we are here debating, in hopes that our evidence will be proven substantial enough to actually support our assumptions. So lets look at your "evidence" shall we?
Joe 2:10 The earth shall quake before them; the heavens shall tremble: the sun and the moon shall be dark, and the stars shall withdraw their shining:
Joe 2:11 And the LORD shall utter his voice before his army: for his camp is very great: for he is strong that executeth his word: for the day of the LORD is great and very terrible; and who can abide it?
Joe 2:31 The sun shall be turned into darkness, and the moon into blood, before the great and the terrible day of the LORD come.
Joe 2:32 And it shall come to pass, that whosoever shall call on the name of the LORD shall be delivered: for in mount Zion and in Jerusalem shall be deliverance, as the LORD hath said, and in the remnant whom the LORD shall call.
First of all we need to establish the context of the passage- Joel is speaking of the coming day of the Lord.
1 Blow a trumpet in Zion,
And sound an alarm on My holy mountain!
Let all the inhabitants of the land tremble,
For the day of the Lord is coming;
Surely it is near,
2 A day of darkness and gloom,
A day of clouds and thick darkness.
As the dawn is spread over the mountains,
So there is a great and mighty people;
There has never been anything like it,
Nor will there be again after it
To the years of many generations.
Notice how he describes the day of the Lord- as a day of clouds and thick darkness.This description continues on through the verse 11 which you posted which goes on to describe the sun and moon being dark and the stars losing their brightness.
Yet this passage says the following
30 “I will display wonders in the sky and on the earth,
Blood, fire and columns of smoke.
31 “The sun will be turned into darkness
And the moon into blood
Before the great and awesome day of the Lord comes.
These events happen BEFORE the day of the Lord comes, Joel is not interchanging the events to say they are one in the same, he is describing two separate events- one IS the day of the Lord the other is BEFORE the day of the Lord comes.
In fact Peter quotes verses 28 -31 in his sermon at Pentecost,
16 but this is what was spoken of through the prophet Joel:
17 ‘And it shall be in the last days,’ God says,
‘That I will pour forth of My Spirit on all mankind;
And your sons and your daughters shall prophesy,
And your young men shall see visions,
And your old men shall dream dreams;
18 Even on My bondslaves, both men and women,
I will in those days pour forth of My Spirit
And they shall prophesy.
19 ‘And I will grant wonders in the sky above
And signs on the earth below,
Blood, and fire, and vapor of smoke.
20 ‘The sun will be turned into darkness
And the moon into blood,
Before the great and glorious day of the Lord shall come.
21 ‘And it shall be that everyone who calls on the name of the Lord will be saved.’
22 “Men of Israel, listen to these words: Jesus the Nazarene, a man attested to you by God with miracles and wonders and signs which God performed through Him in your midst, just as you yourselves know—
23 this Man, delivered over by the predetermined plan and foreknowledge of God, you nailed to a cross by the hands of godless men and put Him to death.
24 “But God raised Him up again, putting an end to the agony of death, since it was impossible for Him to be held in its power.
Peter uses these scriptures to explain the events that were occurring at Pentecost, he is showing that these events were being fulfilled then. Remember as Christ hung on the cross there was darkness for three hours. Perhaps some lunar eclipse occured in conjunction to the life of Christ as well. In any case Peter shows at least some form of fulfillment of the passage in Joel. So if Peter says that these signs in Joel were being fulfilled in his day, isn't it possible that they could happen again as a future fulfillment of the same prophecy? Before the Day of the Lord? As a sign to the Jews who have yet to receive the promises?
There is a moratorium on the fulfillment of the day of darkness and gloom- it will only happen once as Joel says in verse 2:2. Yet there is no moratorium on blood red moons, or darkened suns. We know this to be true, because we witness several blood red moons a year and also solar eclipses.
In fact there is a day of darkness described in the revelation that could be the fulfillment of Joel's Day of the Lord:
10 Then the fifth angel poured out his bowl on the throne of the beast, and his kingdom became darkened; and they gnawed their tongues because of pain,
This happens just before Armageddon, which follows along with Joel's description of the day of the Lord.
Strong's Greek #4656
4656 σκοτόω [skotoo /skot·o·o/] v. From 4655; TDNT 7:423; TDNTA 1049; GK 5031; AV translates as “full of darkness” once. 1 to darken, cover with darkness. 2 metaph. to darken or blind the mind.
Compare this to John's description of the events surrounding the removal of the sixth seal:
12 I looked when He broke the sixth seal, and there was a great earthquake; and the sun became black as sackcloth made of hair, and the whole moon became like blood;
Strong's Greek #3189
3189 μέλας [melas /mel·as/] adj. Apparently a root word; TDNT 4:549; TDNTA 577; GK 3506; Three occurrences; AV translates as “black” three times. 1 black. 2 black ink.
Strong's Greek #4526
4526 σάκκος [sakkos /sak·kos/] n m. Of Hebrew origin 8242; TDNT 7:56; TDNTA 995; GK 4884; Four occurrences; AV translates as “sackcloth” four times. 1 a sack. 1a a receptacle for holding or carrying various things, as money, food, etc. 1b a course cloth, a dark course stuff made especially from the hair of animals. 1c a garment of the like material, and clinging to the person like a sack, which was wont to be worn (or drawn over the tunic instead of the cloak or mantle) by mourners, penitents, suppliants and also by those who like the Hebrew prophets, lead an austere life.
He describes this event as the sun becomes blackened as though it were covered by a black sackcloth . Sackcloth made of hair. It is called sackcloth because it was used for sacks, usually made of goat hair. Think of a sack, if you hold it up to the sunlight, some light will penetrate through it. These OT sacks were likely made from goat hair, woven into a cloth, that was both strong and durable, used to carry and package items of all kinds. These sacks would not have been so tightly woven that they would be stiff, they would be woven more loosely so that they could be made into sacks to carry things, and could also serve as garments for mourning. Again if held up to the sunlight, some light however minute would penetrate through it. And in order for the moon to appear red- the light from the sun would have to reflect off of the surface of the moon- it is not a total darkness as the passage in Matthew describes, and as the OT prophets describe concerning the Day of the Lord.