- Frederick Douglass (Wikipedia)
Frederick Douglass (born Frederick Augustus Washington Bailey, c. February 1817 or 1818 – February 20, 1895) was an American social reformer, abolitionist, orator, writer, and statesman. After escaping from slavery in Maryland, he became a national leader of the abolitionist movement in Massachusetts and New York, becoming famous for his oratory and incisive antislavery writings. Accordingly, he was described by abolitionists in his time as a living counterexample to enslavers’ arguments that enslaved people lacked the intellectual capacity to function as independent American citizens. Northerners at the time found it hard to believe that such a great orator had once been enslaved. It was in response to this disbelief that Douglass wrote his first autobiography.
- Observable universe (Wikipedia)
The observable universe is a ball-shaped region of the universe comprising all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time; the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion. Initially, it was estimated that there may be 2 trillion galaxies in the observable universe. That number was reduced in 2021 to only several hundred billion based on data from New Horizons. Assuming the universe is isotropic, the distance to the edge of the observable universe is roughly the same in every direction. That is, the observable universe is a spherical region centered on the observer. Every location in the universe has its own observable universe, which may or may not overlap with the one centered on Earth.