ultradeep

• ultra-deep
• ultra deep

From ultra- +‎ deep.

ultradeep (not comparable)

1. Very deep; of utmost deepness; superdeep.
   • 1988, United States Congress, Congressional Record‎^[1], Congress, page 11915:

     Continental scientific drilling is an important endeavor, in that it provides information related to the causes of earthquakes and volcanic eruptions, and the occurrence of energy and mineral resources. Continental drilling involves both shallow— 1 to 3 miles— and ultradeep drill holes— 9 to 12 miles through the upper continental crust.

   • 1958, United States Congress, The Oil and Gas Journal: Volume 56, Issue 4‎^[2], PennWell Corporation, page 153:

     West Texas’ future holds more ultradeep wildcats, some successes in Sheffield channel. This will prompt a new look at the Delaware and Val Verde basins.

   • 1962, Joseph Allen Hynek, Challenge of the Universe‎^[3], Scholastic Book Services, pages 40-41:

     On the moon there is no atmosphere to temper the heat of day and the cold of night. In direct sunlight, the rocky terrain bakes at a temperature of over 200°F. during the lunar day, which is 14 Earth days long. And, during the equally long night the surface of the moon lies in an ultradeep freeze, calculated to be 240°F. below zero. In the absence of a protective shield of gas, the surface of the moon is exposed to the full spectrum of sun’s radiant energy, including the ultraviolet radiation which is inimicable to life.

• paultered