Event:
The Harvard-Smithsonian Center for Astrophysics estimates at least 17 billion planets exist that are comparable to the size of the Earth and the Milky Way
More Notable Events on January 7: 1986 U.S. president Reagan proclaims economic sanctions against Libya
1953 President Truman announces development of hydrogen bomb
1942 WW II siege of Bataan starts
1914 1st steamboat passes through Panama Canal
1618 Francis Bacon becomes English lord chancellor
