<p>From <a href="https://books.google.co.uk/books?id=CEk6SZQK0C0C&amp;pg=PA213&amp;lpg=PA213&amp;dq=relative%20motion%20of%20sirius&amp;source=bl&amp;ots=KMbqPxsA0q&amp;sig=A9KHZhHCBcpwcrfTHf7TWQ7eBfU&amp;hl=en&amp;sa=X&amp;ved=0ahUKEwjvqajR2NzOAhXIK8AKHVZ6D5wQ6AEIMjAD#v=onepage&amp;q=relative%20motion%20of%20sirius&amp;f=false" rel="nofollow">Sirius: Brightest Diamond in the Night Sky</a> by Jay B. Holberg we have current distance of Sirius ~8.5ly, closest approach will be ~6.7ly. The intensity of of light from Sirius assuming constant luminosity scales as distance squared, so the intensity (power per unit area at the eye) at closest approach will be: $\left(8.5/6.7 \right)^2 \approx 1.6$ times that today, which is a change of magnitude from about $-1.4$ to about $ -1.6$</p>

CC BY-SA 3.0
2016-08-25T17:27:59.840Z
TLDR: the change will be barely noticeable.
Florin Andrei
CC BY-SA 3.0
2016-08-26T10:05:24.437Z
It would still be measurably dimmer than the brightest 3 planets, but I think a change from -1.6 to -1.4 would be visibly noticeable, especially if you had 2 objects of that brightness side by side.
userLTK
CC BY-SA 3.0
2016-08-25T13:49:37.810Z
2016-08-25T14:33:30.287Z
2016-08-25T14:33:30.287Z
Conrad Turner
<p>Preferably in terms of percentage. As a layman, visual apparent magnitude means little to me.</p>

CC BY-SA 3.0
2016-08-25T13:20:53.283Z
How can you express brightness in terms of percentage?
Sir Cumference
<observational-astronomy>
How bright will Sirius be when it's closest to the solar system?
Mike Pollard
# How bright will Sirius be when it's closest to the solar system?

(Asked by: username_0 on 2016-08-25)

Preferably in terms of percentage. As a layman, visual apparent magnitude means little to me.

**Tags:** observational-astronomy

> **Comments:**
> **username_1**: How can you express brightness in terms of percentage?  

---

## 1 answers

### Answer by username_2 on 2016-08-25. Score: 5

From [Sirius: Brightest Diamond in the Night Sky](https://books.google.co.uk/books?id=CEk6SZQK0C0C&pg=PA213&lpg=PA213&dq=relative%20motion%20of%20sirius&source=bl&ots=KMbqPxsA0q&sig=A9KHZhHCBcpwcrfTHf7TWQ7eBfU&hl=en&sa=X&ved=0ahUKEwjvqajR2NzOAhXIK8AKHVZ6D5wQ6AEIMjAD#v=onepage&q=relative%20motion%20of%20sirius&f=false) by Jay B. Holberg we have current distance of Sirius ~8.5ly, closest approach will be ~6.7ly. The intensity of of light from Sirius assuming constant luminosity scales as distance squared, so the intensity (power per unit area at the eye) at closest approach will be: $\left(8.5/6.7 \right)^2 \approx 1.6$ times that today, which is a change of magnitude from about $-1.4$ to about $ -1.6$

> **Comments:**
> **username_3**: TLDR: the change will be barely noticeable.  
> **username_4**: It would still be measurably dimmer than the brightest 3 planets, but I think a change from -1.6 to -1.4 would be visibly noticeable, especially if you had 2 objects of that brightness side by side.  

---

