If a planet is 150 light years away and we see it through the Hubble telescope are we looking at the planet?

Question

are we looking 150 light years into the past?

THERE IS A HUGE DIFFERENCE BETWEEN 150 YEARS AND 150 LIGHT YEARS!

Answer 1

Technically, you'd be 'looking' at the light that travelled from the planet 150 years ago. When you observe an object, whether it be a far away planet or star or your computer screen in front of you, you are observing the light that was emitted or reflected from that object. In the case of the computer screen, since it is so close, the light you are observing is only milliseconds old. But if you are observing light from an object 150 light years away, the light that is travelling into your eyes is 150 years old.

So, if you had a telescope more powerful than Hubble and could get detailed images of the surface of the planet, the content of those images will be objects 150 years in the past.

Answer 2

If it is 150 light years away and we look at it through anything we are seeing it how it was 150 years ago.

The only thing the telescope would do would be to give you a better image of it. No telescope can get a view of a planet that far away by any ordinary methods though.

Answer 3

When you are seeing something in the night sky, you are seeing light that has been travelling for millions or billions of years. That star probably died a long time ago. It's the same principle with deep space imagery. The photos of the horsehead nebula were made from light that has been travelling for eons. It probably looks nothing like the photos now. The information we have on these stars is extraordinarily dated in this respect. It's probably no longer true for the most distant stars. The more nearby stars, however, only take a few years for the light to reach us, making the observations more valid. As for the planetary composition bit, you're exactly right. Different elements have different signatures of reflected light that astronomers can measure. How exactly, I'm unsure.

Answer 4

Technically yes; however, even the Hubbell can’t resolve an object that small at that distance. What we usually see is the change in the light curve of the parent star as a large planet passes between us and it’s star. Some times the planet (large gas giants mostly) have gasses in there atmospheres that can be detected spectroscopically as the light from the parent star passes through it.

Answer 5

Yes.

Also... we most likely are not seeing it directly. None of the planets discovered thus far have been directly observed (except for 1 large one recently, but that is by some extraordinary methods).

Even with all the indirect methods of "observing" planets far away, we are still observing the light that is 150 years old (or how ever far away that planet is).

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