Almost everything that exists in this world can be an object of Torah study either directly or indirectly.
While not everything is actually discussed in the Torah, there is not a single thing that is off limits.
This is true not only in regard to the vastness of the Torah as a whole, but also in regard to the specific area of halacha and legal decisions.
In this realm, as well, practically every topic can serve as a theme for questioning, clarifications and halachic rulings.
There are, for instance, Torah discussions on issues as diverse as local and international politics, women’s fashion and university grants.
If there are areas that the halacha has not yet addressed, it is not because they have been overlooked or cannot be discussed.
Rather, they have not yet been tackled by the sages, whether by coincidence, out of fear of controversy or for a variety of other reasons.
Conversely, while individual scholars may sometimes speak nonsense about quasi-halachic issues, such statements are not a failing of the Torah.
They are the problem of those who are speaking without understanding the matter at hand.
–Rabbi Adin Steinsaltz
From an essay "We Will Come Back to You," Nov. 3, 2009, by Rabbi Adin Steinsaltz