Short answers, pulled from the story.
Pierre Gassendi (1592-1655) was a French Catholic priest, philosopher, astronomer, and mathematician. He is best known for being the first person to observe the transit of a planet across the Sun, publishing the first data on the transit of Mercury in 1631, and for his philosophical project reconciling Epicurean atomism with Christianity.
In 1631, Pierre Gassendi became the first person in recorded history to observe the transit of a planet across the Sun, watching the transit of Mercury that Johannes Kepler had predicted. He also attempted to observe the transit of Venus that December, but the event occurred at night in Paris.
Gassendi held that the evidence of the senses was the only convincing basis for knowledge of the physical world, opposing Descartes's view that the mind could achieve certain knowledge through reason alone. Gassendi also claimed priority in stating the mind-body problem explicitly, reacting to Descartes's mind-body dualism. His objections appeared in print in 1641 as the Fifth Set of Objections in Descartes's works.
The Syntagma philosophicum, published posthumously in his collected works in 1658, is considered Gassendi's most significant philosophical work. He also published the well-received De vita, moribus, et doctrina Epicuri libri octo in 1647 and the Syntagma philosophiae Epicuri in 1649, both central to his project of reconciling Epicurean atomism with Christian doctrine.
Gassendi argued against eating meat, considering it an obstacle to achieving a divine vision. He supported vegetarianism with arguments from medicine, history, and scripture, though he was not himself a vegetarian. He admitted that "if I were wise, I would abandon meat bit by bit, and nourish myself solely on the gifts on the earth."
Pierre Gassendi is memorialized by a large crater on the Moon named after him, and by a bronze statue by sculptor Joseph Ramus erected at Digne in 1852 through public subscription. He was born near Digne in southern France and held the Provostship of the Cathedral Chapter there from 1634 until his death in 1655.