# Re: supernova rings

Glenn R. Morton (grmorton@waymark.net)
Sun, 03 May 1998 15:45:38 -0500

At 12:19 AM 5/3/98 -0600, Bill Payne wrote:
>Glenn R. Morton wrote:
>
>> The reflection points along the old rings of dust lie along a parabolic
path.
>
>> Does this make it clear?
>
>No, but I have ordered the book, and have put the question to an
>astromoner. I'll get back with you.

Let me try again. The light ring is a reflection off of gas that lies
between the earth and the supernova.

dust
light travels / \then reflects back to earth
to dust / \
/ \
/ \
star----light travels to earth directly-------->earth

The distance from the star to the earth is 169,000 light years. The
diameter of the ring is 400 light years, giving a 200 lightyear radius.

Pythagorean theorem tells us that the travel path of the light from the
star to the dust then to the earth is

d
/|\
a / | \ b
/ 200 \
/ | \
s--169000--e

to find the travel distance for side a we have

a=sqrt[(169000/2)^2 +(200)^2] =84500.2366
b=sqrt[(169000/2)^2 +(200)^2] =84500.2366

The total travel path from the star to the dust to the earth is:
169,000.47 lightyers compared with the 169,000 lightyears direct distance.
With the ring as I drew it, the reflected light from the ring should get
here about 6 months after the light from the initial explosion.

The inner ring is at the star, not at the dust.

Does this help?
glenn