science
It is the universe's ultimate speed limit — fast enough to loop around the Earth several times in the blink of an eye, and nothing we know of moves faster.
Light's speed of roughly 300,000 kilometers per second is a fundamental constant arising from the properties of electromagnetic fields, and it represents an absolute upper limit on how fast anything carrying energy or information can travel, per our current understanding of physics. At that speed, light could circle the Earth about seven and a half times in a single second.
1,000 km/s and 30 km/s are both far slower, more in line with fast spacecraft or orbital speeds, and confusing them highlights just how vast light speed really is compared to anything we experience directly.
Because light takes measurable time to travel even short cosmic distances, looking at distant stars means seeing them as they were in the past, sometimes millions of years ago.
science
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