The Large Hadron Collider is back up and running, after an upgrade process that lasted nearly four years.
- The massive, 17-mile particle accelerator was restarted on Tuesday for a new batch of experiments.
- The Collider has been out of operation since 2018 for technical upgrades that give it more power and better ability to collect data.
- If you could get the answer to any scientific mystery, what would it be?