When will the temple be rebuilt? What signs could I look for?
If you are asking for prophecy, obviously we can’t answer. But halachically and practically: according to the Rambam, we are commanded to build the Third Temple at all times, as listed in one of the 613 mitzvot (Rambam, Beit HaBchira 1, 1; Sefer HaMitvot Mitzva 20). Although he also writes (M’lachim 1, 2) that beforehand we should anoint a king and erase Amalek, because of the difficulties involved in observing those two mitzvot (see the Netziv, Dvarim 17, 15, who writes that if the people don’t want a king and for example, prefer a democracy, than we are exempt because of Pikuach Nefesh; additionally, Amalek is unidentifiable and probably no longer exists- which surely can’t mean we will never be able to build the Temple!), we have no choice but to go ahead with the third obligation (see final paragraph). It’s worthy to mention the Sefer Hachinuch (95) who holds that this mitzvah applies only when the majority of Jews are living in the Land of Israel, which statistically will be in just 17 years from now (5790/2030) if not sooner (Demographer Prof. Sergio Della-Pergola of Hebrew University, in a most extensive survey, the Jerusalem Report, 24/24/97)! Either way, it’s clear that in our generation, we should be preparing as much as possible, through researching, funding and constructing the vessels and the architectural plans (see lind: http://www.templeinstitute.org/about.htm ), but most importantly, educationally and politically preparing the groundwork to “want” the Beit MaMikdash. Despite the obligation to try as much as we can, the Talmud (Megilla 17a) informs us that the stages of redemption are as listed in the Shmoneh Esreh prayer (which in fact, our generation can testify, is totally accurate!): revival of the deserted Land of Israel, then mass aliya, then reviving the Sanhedrin, then rebuilding the Beit HaMikdash, and finally the coming of Mashiach Ben David. In other words, we should be working, at least as much on renewing the Sanhedrin and convincing people to want to run the State according to Torah ideals, because that’s going to come first. Interestingly, for the past 3 years, most children entering first grade in Israel, have been enrolled in religious education, and apparently that’s the way it’s going to be from now on. In other words, in 13 years from now, the army is going to look different; in 16 years, universities, as well, and in 20 years, the State of Israel will be significantly more religious (already about 30% are orthodox, and another 50% traditional, see link: http://www.idi.org.il/אירועים/כנסים-וימי-עיון/דוח-גוטמן-אבי-חי/). In other words, Jews should be coming home to Israel, and gentiles should be helping, as well, because things are getting interesting! You don’t have to “look for signs”- just read the newspaper. Redemption is no longer wishful thinking, but it’s taking place. The pace is up to us and G-d. Ani v’hu hoshe’ah na! With Love of Israel, Rav Ari Shvat