It depends. The planets move. The distance changes. And that delay makes space hard.
Mars and Earth orbit the Sun at different speeds. Sometimes they're on the same side — closest approach is about 54.6 million km. Sometimes they're on opposite sides — farthest point is 401 million km. That's a 7x difference in distance.
Light travels at 299,792 km/s. At closest approach, light takes about 3 minutes to reach Mars. At farthest, about 22 minutes. Most of the time, it's somewhere in between — about 12-15 minutes.
If you're driving a rover on Mars from Earth, you're not really driving. You're sending commands that arrive 10-20 minutes later, and waiting another 10-20 minutes for a response. The rover can't stop for you. If it hits a rock, you won't know until the picture arrives half an hour later.
This is why Mars rovers are semi-autonomous. They drive themselves, avoid obstacles themselves, and only check in with Earth every few hours. NASA doesn't "drive" a rover like a video game. They send a destination and a list of do's and don'ts. The rover figures out the rest.
The Moon: 1.3 seconds. Jupiter: 30-52 minutes. Neptune: 4 hours. Proxima Centauri (nearest star): 4.24 years. The Andromeda galaxy: 2.5 million years. Every step out into space adds minutes, then years, then geological ages.
Pick a destination and guess the light travel time.
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