Light years, are basically how far would does light travel, at roughly 186,000 miles a second, if it were to go for a year.
you use light years, and other units
light year
lightyears
You need two places to measure the distance between them. Rio de Janeiro is given in the question, the other place is missing and needs to be added.
well they are millions of miles away from each other
Either estimate the distance, or measure it. A compass is used by navigators to measure the distances between successive points, and to compare distances against the scale printed on the chart.
what is the type of star used by the Hubble to measure the distance to other galaxies.
Miles is a measure of distance and hours is a measure of time. There is no direct relationship between the two and it is not possible to convert from one to the other.
With a tape measure. How much longer does it need to be? 1/2 inch on each end.
-- Measure the distance between two points.-- Measure the time it takes the jet to fly from one point to the other one.-- The speed of the jet between the two points is(the distance between them)/(the time it takes to fly from one to the other)
Because no other unit of distance is large enough. The closest star system to us is 4.2 light years away, which is about 25,000,000,000,000 miles.
You use exactly the same instruments to measure speed in the metric system as you use in any other system. For example, a speedometer, or a distance measuring device and a stopwatch. The difference is that these devices are calibrated in metric units, instead of old-fashioned units.