Neptune's windy atmosphere in August 1989. The ice giant Neptune was the first planet located through mathematical predictions rather than through regular observations of the sky.
well slavery was an big issue because it separated the northern and southern states. the northern states realize that slavery was an unnessary inhumane treatment and wanted to abolished it. While the southern states depended on slaves since they worked for free on their plantation. To resolve this they counted 3 free men for 5 slaves until 1808.
In the 1840s and '50s, the party was in conflict over extending slavery to the Western territories. Southern Democrats insisted on protecting slavery in all the territories while many Northern Democrats resisted. The party split over the slavery issue in 1860 at its Presidential convention in Charleston, South Carolina.