4 ms·
While that’s a problem in theory, to moderate accuracy it’s not a practical issue. Most objects in the universe are roughly at rest relative to the cosmic backg
by simonh 5y ago
While that’s a problem in theory, to moderate accuracy it’s not a practical issue. Most objects in the universe are roughly at rest relative to the cosmic background radiation (in other words they don’t see it as Doppler shifted in any particular direction), so we can use that as a common frame of reference. When we’re talking about ballpark integer billions of years, or even to a few decimal places, that’s easily good enough.
- uoaei 5y agoAccuracy? "Now" is an inaccurate (nonsensical, actually) concept except in extremely local conditions.
- simonh 5y agoIt's perfectly sensible given a common frame of reference, which we have thanks to the CMB. Frames of reference aren't local. We have clocks and can measure time on them just fine, and 'now' is just a time on a clock.
- deleted 5y ago[deleted]