Hubble Deep Field. Coordinates: 12h 36m 49.4s, +62° 12′ 58″ The Hubble Deep Field The Hubble Deep Field (HDF) is an image of a small region in the constellation Ursa Major, constructed from a series of observations by the Hubble Space Telescope.
It covers an area 2.5 arcminutes across, about one 24-millionth of the whole sky, which is equivalent in angular size to a 65 mm tennis ball at a distance of 100 metres.
Outer space. The boundaries between the Earth's surface and outer space, at the Kármán line, 100 km (62 mi) and exosphere at 690 km (430 mi).
Not to scale. There is no firm boundary where space begins. However the Kármán line, at an altitude of 100 km (62 mi) above sea level, is conventionally used as the start of outer space in space treaties and for aerospace records keeping. The framework for international space law was established by the Outer Space Treaty, which was passed by the United Nations in 1967. 99942 Apophis. 99942 Apophis (/əˈpɒfɪs/, previously known by its provisional designation 2004 MN4) is a near-Earth asteroid that caused a brief period of concern in December 2004 because initial observations indicated a probability of up to 2.7% that it would hit Earth in 2029.
Additional observations provided improved predictions that eliminated the possibility of an impact on Earth or the Moon in 2029. However, a possibility remained that during the 2029 close encounter with Earth, Apophis would pass through a gravitational keyhole, a small region no more than about 800 m (half a mile) wide, that would set up a future impact on April 13, 2036.
This possibility kept the asteroid at Level 1 on the Torino impact hazard scale until August 2006, when the probability that Apophis would pass through the keyhole was determined to be very small. Arecibo Observatory. The observatory's 1,000 ft (305 m) radio telescope is the world's largest single-aperture telescope.
It is used in three major areas of research: radio astronomy, aeronomy, and radar astronomy. Scientists who want to use the telescope submit proposals that are evaluated by an independent scientific board. Home.
NASA. Coordinates: The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research.