How is distance to stars and other planets determined? I know it is measured in light-years, but how is that determined? If radar or sonar or anything similar were used, it would take longer than we would live to bounce back to us. Could those stars and planets actually be closer than we thought? God bless you, Dennis in OK
Hey brother Dennis!
The stars are surely thousands of light years away, and the other galaxies even billions away. There’s no threat to Biblical authority on that, whether on age of the earth or Big Bang Theory or whatever. Only the closest stars can be accurately measured in their distances from Earth. We do this by “trigonometric parallax.” We take a look at where in the sky a star appears from the vantage point of Earth … then we wait half a year until Earth is on the other side of the Sun (a difference of nearly 200 million miles) and then we take a look at it again. The more different its location seems, compared to the relatively fixed apparent location of the more distant stars … then the closer it is to us.
You can try this yourself right now, by using the distance between your own two eyes in substitution for the distance of Earth in spring to Earth in fall around the sun. Just hold up your finger in front of both eyes, and look at it against a relatively distant background. Now close only your right eye — then only your left eye — left-right-left-right. See it? And the closer your finger is to your face, the more it will appear to have moved in its location relative to the distant background.
However, parallax can only use a gigantic triangle to measure the distance of stars no farther than 4.5 light years away. Most are much further than that. The rest are figured using “stellar evolution” theory to predict the size and brightness of a star … then to look at how much smaller and dimmer it looks from here … to gauge how far away it must be. True, this is flawed. Seyfert-variable stars are used to gauge the distance of even stars in other galaxies. These and super-nova explosions are more reliable. But the distances really are as great as the textbooks say. The “main sequence” on the H-R Diagram, however (all put together from Big Bang Theory and Stellar Evolution Theory), is a non-proven yet taught-as-fact concept. I hope this helps. Say “hi” from all of us at Creation Truth Foundation to all of the brothers and sisters on the campus and at the church!
Sincerely yours, Dr Jackson