PDA

View Full Version : Questions about Voyager 1



Denis12
2006-Oct-05, 11:39 PM
1 How bright or dark will it be at (this) moment where Voyager 1 is at this moment? Is the Sun shining bright or just less bright than a full Moon in our night sky? And what will be its distance from the Sun now?

2 And what wil be the brightness of the Sun at the position of Voyager 1 over 200 years ahead? And how much AU will it be away from the Sun by then?

3 And what will be the brightness of the Sun when Voyager 1 is at 1 Lightyear away from us? Will it be still illuminated of the Sun then?

A lot of thanks for anyone who can help me to answer this questions.

Denis12

astromark
2006-Oct-06, 04:48 AM
I live in the southern hemisphere and so see Alpha cent., almost any time I like. It is a double and has one star marginally brighter and one marginally less than our sun. They are 4.2 ly away. from where Voyager know is this double would almost be as bright as Sol. Voyager 1 is almost at the limit of our suns area of influence. She would still be the brightest star but, down to a single point of light. Just brighter than Sirius. Where are you observing from?

ozark1
2006-Oct-06, 07:33 AM
Hold on a mo.

Voyager 1 is just over 100 AU from the sun (a little further than Sedna at perihelion). That's not very far at all - though it is near the heliopause.

This means for V1 - the Sun is 10,000 times fainter than from earth - 10 magnitudes fainter or -17.2. That is 100 times brighter than the full moon, and a million times brighter than Sirius.

In 200 years time V1 will be at around 700 AU. This isn't as far as Sedna at aphelion (975 AU). At this point the sun would be 500,000 times fainter than from earth, 14 and a bit magnitudes fainter or -13. This is still twice as bright as the full moon and twenty thousand times brighter than Sirius.

At 1 light year - approx 50,000 AU (and about 15,000 years travel time) - the sun would be getting fainter. It would be 15 times brighter than Alpha Centauri, 5 times brighter than Sirius at -4.

antoniseb
2006-Oct-06, 11:56 AM
from where Voyager know is this double would almost be as bright as Sol. Voyager 1 is almost at the limit of our suns area of influence.

You have a misunderstanding of what fraction of a light year Voyager 1 is away from the Sun. Voyager 1 has travelled about one part in 3000 the distance to Alpha Centauri (but not in the right direction). For Voyager, no star but the Sun has changed brightness appreciably.

Denis12
2006-Oct-06, 12:36 PM
I live in the southern hemisphere and so see Alpha cent., almost any time I like. It is a double and has one star marginally brighter and one marginally less than our sun. They are 4.2 ly away. from where Voyager know is this double would almost be as bright as Sol. Voyager 1 is almost at the limit of our suns area of influence. She would still be the brightest star but, down to a single point of light. Just brighter than Sirius. Where are you observing from?

I am observing from the Netherlands ,very far from New Zealand.

astromark
2006-Oct-07, 12:16 AM
Oops...! OK ... Wrong again, I'm so good at this.
Yes I thought it was much further out and in the right direction.
Sorry for letting the facts get fogged by what was a perfectly simple answer. Thanks for taking the time to steer me right. Just a tad wiser, mark.