4. Distance of the nearest star is 4.0 light-years.
Express it in kilometres.
[Ans. 3.784 x 10 km]
Answers
Answer:
As a matter of fact, I can.
A light-year is the distance that light will travel in one year.
A year is a funny thing, as it is the time it takes for the Earth to make one transit around the sun. It takes about 365 days + 6 hours + 9 minutes + 9.76 seconds.
Of course, due to the precession of the earth’s axis, you may choose a slightly shorter (~ 20 mins) year. And there are additional definitions of a year, but it turns out in this context they are moot: by convention, we use 365.25 days per year when computing light years.
So, given:
299,792.458 km/sec - exact speed of light in a vacuum
365.25 - accepted number of days in a year for defining a light-year
86,400 - exact number of seconds per day
Multiply them all together and you get:
9,460,730,472,580.80 km / light year exactly. Now multiply this by four (for four years) and get:
37,842,921,890,323.20 km/four light years exactly.
Incidentally, the nearest star is Proxima Centauri. It is currently about 4.26 light years from Earth - I can’t find a more precise distance - but is approaching us a 22 km/second!
Explanation:
Answer:
As a matter of fact, I can.
A light-year is the distance that light will travel in one year.
A year is a funny thing, as it is the time it takes for the Earth to make one transit around the sun. It takes about 365 days + 6 hours + 9 minutes + 9.76 seconds.
Of course, due to the precession of the earth’s axis, you may choose a slightly shorter (~ 20 mins) year. And there are additional definitions of a year, but it turns out in this context they are moot: by convention, we use 365.25 days per year when computing light years.
So, given:
299,792.458 km/sec - exact speed of light in a vacuum
365.25 - accepted number of days in a year for defining a light-year
86,400 - exact number of seconds per day
Multiply them all together and you get:
9,460,730,472,580.80 km / light year exactly. Now multiply this by four (for four years) and get:
37,842,921,890,323.20 km/four light years exactly.
Incidentally, the nearest star is Proxima Centauri. It is currently about 4.26 light years from Earth - I can’t find a more precise distance - but is approaching us a 22 km/second!