Both would be equally disastrous as it would mean the end of Earth.
The sun exploding would be more immediate. Within about 8 minutes, the Earth would be showered with enormous amounts of heat and radiation which would rapidly kill all forms of life and possibly disintegrate the planet itself (I'm not up on the geophysics of this scenario, so I don't really know).
If gravity disappeared, I think the most immediate noticeable change would be people who are walking would immediately start moving up into the sky. At an estimated 10 ft/second climb rate, people would reach 15,000 feet altitude (which is about where hypoxia starts to set in) in about 25 minutes.
Or maybe I'm wrong and the moment gravity disappeared the Earth's crust would immediately shatter and we'd all be inundated with liquid hot magma.
Thank you for your thoughtful and information-filled reply SP. I appreciate it. If you could choose which way to go which would it be? Which of the two would you choose? Happy Friday to thee! :)
This post was edited by RosieG at January 31, 2020 5:29 PM MST
Faster? Hard to say. Even though the radiation from the sun takes 8.3 minutes to get to us, the ejecta from an explosion would take longer. Let's say the radiation destroys the earth in about 2 minutes. So that is about ten minutes. If gravity disappeared, there are too many possibilities and variables to make a good prediction, but 10 minutes is probable. Let's call it a tie. Watch this.
SaltyPebble 