2024 will be the second straight "hottest year" on record. But it wasn't supposed to be as hot as it was, coming in far ahead of 2023's alarming global temperature spike.
Threat level: For reasons climate scientists don't yet fully understand, 2024 is likely to temporarily eclipse the Paris Agreement's 1.5°C temperature target, when compared to preindustrial levels.
NASA's Parker Solar Probe completed the closest-ever approach to the Sun by a human-made spacecraft, coming within 3.8 million miles of the solar surface.
Why it matters: NASA scientists received a signal from the probe late Thursday night after several days of silence while it conducted the flyby. The data collected during the historic approach will help scientists better understand the Sun.