Last week, NASA’s science rover “Perseverance” landed successfully on Mars, to jubilant cheers from scientists back home.
Mission managers at NASA’s Jet Propulsion Lab near Los Angeles had been waiting anxiously for confirmation that the craft had landed safely.
Because it takes radio waves 11 minutes to reach Earth from Mars, “Perseverance” had already settled on the surface of the Red Planet by the time news of its safe arrival reached scientists back on Earth. NASA had to endure a nerve-wracking wait before they got the verification.
We encounter this time lag throughout our universe.
The light from our own Sun takes 8 minutes to reach Earth. Light from Pluto takes 5 hours. It takes 8 years for the light from the “Dog Star” Sirius to reach our planet.
This time lag means that with stars extremely distant from us, we’re actually seeing them now as they were thousands of years ago. It takes that long for their light to travel to us.
It sometimes seems as though there’s a similar “time lag” between our brains and our hearts.Read more