The Earth itself groans in anticipation.
There are three different trumpet sounds listed in the Torah, the Tekiah, Shebarim and Teruah with three different meanings. One thing I've noticed about these trumpet sounds from the sky is they're all the Tekiah.
Numbers 10, 1 And the Lord spoke to Moses, saying:
2 “Make two silver trumpets for yourself; you shall make them of hammered work; you shall use them for calling the congregation and for directing the movement of the camps. 3 When they sound a long blast with them (Tekiah), all the congregation shall gather before you at the door of the tabernacle of meeting.
4 If they sound a long blast with one, then the leaders, the heads of the divisions of Israel, shall gather to you. 5 When you sound short blasts, the camps that lie on the east side shall then begin their journey.
6 When you sound short blasts the second time, then the camps that lie on the south side shall begin their journey; short blasts shall they sound for their journeys. 7 And when the assembly is to be gathered together, you shall sound a long blast, but not a short blast.
8 The sons of Aaron, the priests, shall blow the trumpets; and these shall be to you as an ordinance forever throughout your generations.
Numbers 10:3
וְתָקְעוּ בָּהֵן וְנוֹעֲדוּ אֵלֶיךָ כָּל־הָעֵדָה אֶל־פֶּתַח אֹהֶל מוֹעֵד
Tekiah תקיעה refers to the long blasts
As with the silver trumpets so with the shofar.
Lot's of good information here.
The Significance of the Shofar (שופר)
http://www.betemunah.org/shofar.html
The Watchman
http://www.betemunah.org/
4 - Four Traditoinal Jewish Shofar Calls or Blasts
https://www.youtube.com/watch?v=grZDPCKORGg
I just stumbled on this today...
Babylonian Talmud: Tractate Sanhedrin
Folio 97a
The tabernacle of David ha-nofeleth [that is fallen].'1 He replied, 'Thus hath R. Johanan said: in the generation when the son of David [i.e., Messiah] will come, scholars will be few in number, and as for the rest, their eyes will fail through sorrow and grief. Multitudes of trouble and evil decrees will be promulgated anew, each new evil coming with haste before the other has ended.'
Our Rabbis taught: in the seven year cycle at the end of which the son of David will come-in the first year, this verse will be fulfilled: And I will cause it to rain upon one city and cause it not to rain upon another city;2 in the second, the arrows of hunger will be sent forth;3 in the third, a great famine, in the course of which men, women, and children, pious men and saints4 will die, and the Torah will be forgotten by its students; in the fourth, partial plenty;5 in the fifth, great plenty, when men will eat, drink and rejoice, and the Torah will return to its disciples; in the sixth, [Heavenly] sounds; 6 in the seventh, wars; and at the conclusion of the septennate the son of David will come. R. Joseph demurred: But so many septennates have passed, yet has he not come! — Abaye retorted: Were there then [Heavenly] sounds in the sixth and wars in the seventh! Moreover, have they [sc. the troubles] been in this order7 !
http://www.come-and-hear.com/sanhedrin/sanhedrin_97.html