"Sakanoboru" has the 2 meanings as the ascending physically and going back in time . This phrase is used more often as the latter . No doubt this phrase must be used in the Japanese subtitle of the movie named "Back to the future" 時間をさらに遡る(sakanoboru) go further back in time FYI, 逆　of 遡　means the opposite direction .

Hi ascend further to (something) eg. Ascending further to the 15th century. - sara ni 更に　＝　more / further - sakanobotte 　遡って (verb) sakanobru 遡る = ascend / trace (something) back