<p>A recent estimation of the <a href="https://en.wikipedia.org/wiki/Hubble%27s_law" rel="nofollow noreferrer">Hubble constant is 71.9 (km/s)/Mpc</a>.</p>

<p>This means there is an expansion of </p>

<p>$$\left(71.9\ \mathrm{\frac{km}{s\ Mpc}}\right)\left(\mathrm{\frac{60\ s}{min}}\right)\left(\mathrm{\frac{60\ min}{hr}}\right)\left(\mathrm{\frac{24\ hr}{day}}\right)\left(\mathrm{\frac{365\ day}{yr}}\right) = 2,267,438,400\ \mathrm{\frac{km}{yr\ Mpc}}$$</p>

<p>To apply this expansion over a light year:</p>

<p>$$
\frac{2,267,438,400\ \mathrm{(km/yr)/Mpc}}{3,261,564\ \mathrm{lyr/Mpc}} = \boxed{695.2\ \mathrm{\frac{km/yr}{lyr}}}
$$</p>

<p>which is about $7.3483\times10^{-11}\ \%$ per year or $432\ \mathrm{miles/year}$.  </p>

<p>A linear light year of space expands by 695.2 km/yr with a given Hubble constant of 71.9 (km/s)/Mpc.</p>

<p>Edit:
A better measurement released on 2018-02-22 using parallax found the Hubble constant to be <a href="http://imgsrc.hubblesite.org/hvi/uploads/science_paper/file_attachment/308/finalpass5.pdf" rel="nofollow noreferrer">73.45 ± 1.66 (km/s)/Mpc.</a></p>

CC BY-SA 3.0
2017-07-27T23:50:10.197Z
2018-03-01T09:16:44.743Z
2018-03-01T09:16:44.743Z
Zamicol
<p>Now that we know that the universe is expanding, how much does a linear lightyear of space expand currently in a year?</p>

<expansion>
How much does a linear lightyear of space expand in a year?
Zamicol
# How much does a linear lightyear of space expand in a year?

(Asked by: username_0 on 2017-07-27)

Now that we know that the universe is expanding, how much does a linear lightyear of space expand currently in a year?

**Tags:** expansion


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## 1 answers

### Answer by username_0 on 2017-07-27. Score: 8

A recent estimation of the [Hubble constant is 71.9 (km/s)/Mpc](https://en.wikipedia.org/wiki/Hubble%27s_law).

This means there is an expansion of

$$\left(71.9\ \mathrm{\frac{km}{s\ Mpc}}\right)\left(\mathrm{\frac{60\ s}{min}}\right)\left(\mathrm{\frac{60\ min}{hr}}\right)\left(\mathrm{\frac{24\ hr}{day}}\right)\left(\mathrm{\frac{365\ day}{yr}}\right) = 2,267,438,400\ \mathrm{\frac{km}{yr\ Mpc}}$$

To apply this expansion over a light year:

$$
\frac{2,267,438,400\ \mathrm{(km/yr)/Mpc}}{3,261,564\ \mathrm{lyr/Mpc}} = \boxed{695.2\ \mathrm{\frac{km/yr}{lyr}}}
$$

which is about $7.3483\times10^{-11}\ \%$ per year or $432\ \mathrm{miles/year}$.

A linear light year of space expands by 695.2 km/yr with a given Hubble constant of 71.9 (km/s)/Mpc.

Edit:
A better measurement released on 2018-02-22 using parallax found the Hubble constant to be [73.45 ± 1.66 (km/s)/Mpc.](http://imgsrc.hubblesite.org/hvi/uploads/science_paper/file_attachment/308/finalpass5.pdf)


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