U.S. President Joe Biden joined former Democratic presidents and others to honor longtime human rights advocate and storied political family matriarch Ethel Kennedy at a memorial service in Washington ...
The universe began with a vast explosion that generated space and time, and created all the matter and energy in the universe. Exactly what triggered this sudden expansion remains a mystery.
It contains about 10,000 galaxies from all different epochs of cosmic history, with the faintest existing when the universe was less than 500 million years old. Hayes' group studied a small sample ...