Question About Pleiades and Light Speed (more specifically HD 23514)

As we all know, the further we gaze into our Universe the further back in time we look. Or at least that's what they say on the science channel

Example, when we look at The Great Orion Nebula, we're not seeing what it looks like right this second, we see what it looked like in the distant past. Reason being, it takes centuries, millennia, etc for light to reach us from deep space.

Now, located approximately 400 light years from Earth is the constellation Pleiades. (see link below)
en.wikipedia.org...

Within the Pleiades constellation is the star HD 23514 (see link below)
www.gemini.edu.../259

Astronomers are speculating that this star [HD 23514], has particles orbiting it that are the result of planets colliding and or forming.

So my questions are these; is it possible that by now the planet(s) might be fully formed, but due to the distance from Earth it only appears to be forming? Also, if we are looking at images from the past, than how for back in time are we looking in regards to HD 23514?

I just figured this was a thought provoking question. Please leave examples explaining your answer(s) if you can! Thank!

FOOT NOTE: I am aware of the ancient alien conspiracy theory regarding the Pleiades. That is NOT what this post is about.

I'm no scientist, but I'm pretty sure it takes more than 400 years for a planet to form.

originally posted by: ScientiaFortisDefendit
I'm no scientist, but I'm pretty sure it takes more than 400 years for a planet to form.

It's 400 light years not 400 years.

Not sure what the equation is but it's more of a measure of distance than time. (Or so me thinks.)

Edit - sorry op but I have no answer for your question.

originally posted by: minusinfinity

originally posted by: ScientiaFortisDefendit
I'm no scientist, but I'm pretty sure it takes more than 400 years for a planet to form.

It's 400 light years not 400 years.

Not sure what the equation is but it's more of a measure of distance than time. (Or so me thinks.)

Edit - sorry op but I have no answer for your question.

If we're seeing something 400 light years away, we're seeing it as it was 400 years ago. If we see that an object such as a planet is forming, it's still forming. A light year is simply the distance that light travels over a single year.

originally posted by: ScientiaFortisDefendit
I'm no scientist, but I'm pretty sure it takes more than 400 years for a planet to form.

Correct. The current estimates is that it took about 600 million years to form earth, from 4.4 Ga to 3.8 Ga. And HD23514 is only 400 light years away.

originally posted by: minusinfinity

originally posted by: ScientiaFortisDefendit
I'm no scientist, but I'm pretty sure it takes more than 400 years for a planet to form.

It's 400 light years not 400 years.

Not sure what the equation is but it's more of a measure of distance than time. (Or so me thinks.)

Edit - sorry op but I have no answer for your question.

Did you just post that? Really? And you admitted that you don't know the formul....

Let me indulge you.

A light year (also referred to as an astronomical unit) is a measurement of DISTANCE. The distance that light travels in one year. 5.8786×10^12 miles.

So if something is 400 AU away from Earth, we are seeing the cosmic structure as it existed 400 years ago. The question the OP asks is whether the structure in question could have formed a planet by now. If it were possible, then the planet would only be 400 years old.

400 years is very short time when it comes to planet formation. It would take probably millions of years.

HD 23514 lies approximately 440 ly away from us.
arxiv.org...

originally posted by: F4guy

originally posted by: ScientiaFortisDefendit
I'm no scientist, but I'm pretty sure it takes more than 400 years for a planet to form.

Correct. The current estimates is that it took about 600 million years to form earth, from 4.4 Ga to 3.8 Ga. And HD23514 is only 400 light years away.

I was being a bit sarcastic. The Bronze Age was much longer than that for pete's sake.

An astronomical unit is a unit of measurement equal to 149.6 million kilometers, the mean distance from the center of the earth to the center of the sun.

1 light year = 63 239.7263 Astronomical Units.

originally posted by: ScientiaFortisDefendit

originally posted by: minusinfinity

originally posted by: ScientiaFortisDefendit
I'm no scientist, but I'm pretty sure it takes more than 400 years for a planet to form.

It's 400 light years not 400 years.

Not sure what the equation is but it's more of a measure of distance than time. (Or so me thinks.)

Edit - sorry op but I have no answer for your question.

Did you just post that? Really? And you admitted that you don't know the formul....

Let me indulge you.

A light year (also referred to as an astronomical unit) is a measurement of DISTANCE. The distance that light travels in one year. 5.8786×10^12 miles.

So if something is 400 AU away from Earth, we are seeing the cosmic structure as it existed 400 years ago. The question the OP asks is whether the structure in question could have formed a planet by now. If it were possible, then the planet would only be 400 years old.

Okay I understand thanks.

take care.

originally posted by: Kronzon
As we all know, the further we gaze into our Universe the further back in time we look. Or at least that's what they say on the science channel

Example, when we look at The Great Orion Nebula, we're not seeing what it looks like right this second, we see what it looked like in the distant past. Reason being, it takes centuries, millennia, etc for light to reach us from deep space.

Now, located approximately 400 light years from Earth is the constellation Pleiades. (see link below)
en.wikipedia.org...

Within the Pleiades constellation is the star HD 23514 (see link below)
www.gemini.edu.../259

Astronomers are speculating that this star [HD 23514], has particles orbiting it that are the result of planets colliding and or forming.

So my questions are these; is it possible that by now the planet(s) might be fully formed, but due to the distance from Earth it only appears to be forming? Also, if we are looking at images from the past, than how for back in time are we looking in regards to HD 23514?

I just figured this was a thought provoking question. Please leave examples explaining your answer(s) if you can! Thank!

FOOT NOTE: I am aware of the ancient alien conspiracy theory regarding the Pleiades. That is NOT what this post is about.

What is really interesting is our perception of reality. It is possible that not one of those stars we see exist anymore. They could all be gone. I am not sure what star is the nearest (besides our sun), but lets say it is a star in Pleiades constellation that you state is 400 light years away, it may have had a supernova experience or been lost into a black hole and disappeared 400 years ago. I guess we will know the next time we look up

We use historic perception that the stars will be there tomorrow but in reality we have no proof. Weird huh?

a reply to: govmule

The closest star (besides the Sun) is Proxima Centauri at a whopping 4.24 ly away.

It's pretty cool to speculate that stars aren't even there anymore, but we've gotten good at determining which stars are going to blow up. None of the stars in the Pleiades are giving any signs of going supernova.

Now Betelgeuse...that's 640 ly away and is giving lots of signs of going supernova. We can't pin it down but we know it's going to happen. That's exciting!

Just an FYI, I know nothing of space travel or light years, as you may have noticed. I never even knew the distance of a light year till I got home and looked it up long after I posted this.

Granted, I should, should've researched it better. But hey, my area of expertise is film, history and philosophy. Maybe I should stick to those topics

Thanks for setting me straight. Also, I know it takes millions of years for planets to form I just was unsure about light speed and distance. Thanks again everyone!

a reply to: Kronzon

May I just ask a question, how is that even possible with education of today?

If you are really interested how planets are formed, how long it takes and how we use star watching as look in cosmic past, I suggest you check new series Cosmos. Dr. Tyson did great job explaining planet forming, including our own planet. You can watch series from 1st episode for free, just follow the link by clicking.

Some stuff I didn't know and I love astronomy, in beginning of its existence, moon was much closer to earth. Just imagine moon at 10th of its distance, would form waves that are 1000 times bigger - how spectacular view of moon would be...

ps. I was hopping that this was not another 'Pleiades cult' post... thank you for not being into that...

a reply to: Kronzon

No, it takes millions of years for a planet to form. The Pleiades are only 400 ly away - if they had planets, we'd see them for sure. Well. That being said, not all exoplanets can be detected using our current technology.

Regards

a reply to: swanne

Not necessarily...

The way we see planets, note that most of planets we register are close to its star and are large enough for our instruments to register them. I doubt we have capabilities to see yet planets similar to earth at that distance, or even closer yet, but we might get technology in future...

There was youtube video that shows how how we detect planets, and how long it takes for space telescope to determine if watched object is planet or not, and how big is the orbit... I tried to look through my history, but I can't find it...

a reply to: SuperFrog

Determining the presence of a planet is sometime no easy job. Take a look at all the confusion around Vega's possible system (and Vega is much closer to Earth than the Pleiades are):

a 2002 paper hypothesizes that the lumps are caused by a roughly Jupiter-mass planet on an eccentric orbit. Dust would collect in orbits that have mean-motion resonances with this planet—where their orbital periods form integer fractions with the period of the planet—producing the resulting clumpiness.[17]

In 2003 it was hypothesized that these lumps could be caused by a roughly Neptune-mass planet having migrated from 40 to 65 AU over 56 million years,[18] an orbit large enough to allow the formation of smaller rocky planets closer to Vega. The migration of this planet would likely require gravitational interaction with a second, higher-mass planet in a smaller orbit.[80]

Using a coronagraph on the Subaru telescope in Hawaii in 2005, astronomers were able to further constrain the size of a planet orbiting Vega to no more than 5–10 times the mass of Jupiter.[81] The issue of possible clumps in the debris disc was revisited in 2007 using newer, more sensitive instrumentation on the Plateau de Bure Interferometer. The observations showed that the debris ring is smooth and symmetric. No evidence was found of the blobs reported earlier, casting doubts on the hypothesized giant planet.[82]

Although a planet has yet to be directly observed around Vega, the presence of a planetary system can not yet be precluded. Thus there could be smaller, terrestrial planets orbiting closer to the star.

source: en.wikipedia.org...

It's been more than 10 years now and we still basically don't know.

originally posted by: bhaal
An astronomical unit is a unit of measurement equal to 149.6 million kilometers, the mean distance from the center of the earth to the center of the sun.

1 light year = 63 239.7263 Astronomical Units.

That's right, and I knew that, too. I looked up a light year and I think the source referred to it as "An astronomical unit of measure", which can also apply to a parsec. It was confusing at the moment.

originally posted by: Kronzon
As we all know, the further we gaze into our Universe the further back in time we look. Or at least that's what they say on the science channel

Example, when we look at The Great Orion Nebula, we're not seeing what it looks like right this second, we see what it looked like in the distant past. Reason being, it takes centuries, millennia, etc for light to reach us from deep space.

Now, located approximately 400 light years from Earth is the constellation Pleiades. (see link below)
en.wikipedia.org...

Within the Pleiades constellation is the star HD 23514 (see link below)
www.gemini.edu.../259

Astronomers are speculating that this star [HD 23514], has particles orbiting it that are the result of planets colliding and or forming.

So my questions are these; is it possible that by now the planet(s) might be fully formed, but due to the distance from Earth it only appears to be forming? Also, if we are looking at images from the past, than how for back in time are we looking in regards to HD 23514?

HD 23514 is 440.316 lightyears away so when we look at it we're looking at how it was 440.316 years ago.

As for whether the planets would be fully formed by now, the answer is no. While there are likely more than a couple planet sized bodies they are still being bombarded like our Solar System was near the time it was born.

It takes more than 400 years for a planetary system to settle down into the nice stable thing our Solar System is.

But in several hundred million years or 1 billion years or so they might be. It's fun to imagine a future version of humanity immigrating there when things settle down just as our Sun will have heated up beyond where life is possible on Earth

Incidentally, my current work as an undergrad is helping a study stars like HD 23514 and other more mature ones to characterize the dust around them using the UKIST telescope in Australia.

This will help future generations of space telescopes built to actually take images of small rocky planets around nearby stars.

originally posted by: ScientiaFortisDefendit

originally posted by: bhaal
An astronomical unit is a unit of measurement equal to 149.6 million kilometers, the mean distance from the center of the earth to the center of the sun.

1 light year = 63 239.7263 Astronomical Units.

That's right, and I knew that, too. I looked up a light year and I think the source referred to it as "An astronomical unit of measure", which can also apply to a parsec. It was confusing at the moment.

1 parsec = 3.2616 light year (roughly)

We use parsecs amongst ourselves in astronomy.

lightyears are used to convey distances to the general public since they're more well known and help educate people as to just how vast space is.