# How long would it take light from the sun to reach Ceres?

Nov 5, 2016

Somewhere between $1276$ and $1486$ seconds.

Currently (2016-11-05) $1433$ seconds.

#### Explanation:

Ceres distance from the sun varies between $3.8262 \times {10}^{11} \text{m}$ at perihelion and $4.4541 \times {10}^{11} \text{m}$ at aphelion.

As I write, it is at about $4.297 \times {10}^{11} \text{m}$

The speed of light in vacuum is $2.99792458 \times {10}^{8} {\text{ms}}^{- 1}$

So at perihelion it would take:

$\frac{3.8262 \times {10}^{11}}{2.99792458 \times {10}^{8}} \approx 1276$ seconds

and at aphelion it would take:

$\frac{4.4541 \times {10}^{11}}{2.99792458 \times {10}^{8}} \approx 1486$ seconds

At this time of writing it would take:

$\frac{4.297 \times {10}^{11}}{2.99792458 \times {10}^{8}} \approx 1433$ seconds