Kade Rystalmane
Well-known member
What evidence is there for new star formation?
Star Formation
- Thread starter Kade Rystalmane
- Start date
We have photos of it happening for one thing.
Search the link for some amazing pictures.
Mr Laurier
Well-known member
Direct observation
Kade Rystalmane
Well-known member
So far, none of these responses has actually provided real evidence. Allegedly the process to form a new star takes about a million years according to the scientists that talk about the process. If this is true, how can we say with any credibility (much less certainty) that what is being observed is star "formation" given that we have only been studying stellar life cycles for less than .02% of that amount of time? In other words, what is the actual evidence beyond the say-so of the scientific clergy?
For instance, looking at the Elephant's Trunk nebula example, we have observed previously unobserved stellar objects. They are referred to as proto-stars or newborn stars, but how do we know that? Or are scientists inferring it without it being a necessary implication of what has been observed? Perhaps they are stellar objects that we simply haven't seen before in the brief time we've had the technology to do so "due to obscuration by the thick cloud ('globule body') and by dust surrounding" them and because older technology wasn't up to the job. Just because we started observing them recently doesn't mean they weren't there before, only that we couldn't see them.
For instance, looking at the Elephant's Trunk nebula example, we have observed previously unobserved stellar objects. They are referred to as proto-stars or newborn stars, but how do we know that? Or are scientists inferring it without it being a necessary implication of what has been observed? Perhaps they are stellar objects that we simply haven't seen before in the brief time we've had the technology to do so "due to obscuration by the thick cloud ('globule body') and by dust surrounding" them and because older technology wasn't up to the job. Just because we started observing them recently doesn't mean they weren't there before, only that we couldn't see them.
What would you accept as "real evidence"? We have visual confirmation of stars in all different stages of formation, from the beginning dust cloud condensation all the way through ignition. The situation is analogous to having photos of all different stages of the growth of a redwood tree, from pine cone to seedling to sapling to immature tree to mature tree. No one is ever going to witness the entire 500 year long process in real time from start to finish.
inertia
Super Member
From my notes:
The dense cores of Bok Globules viewed in the infrared and at millimeter wavebands ( especially B335 ) provide the best-studied cases. Fundamentally the molecular cloud collapses and becomes adiabatic, slowing the rate of collapse near the core where hydrostatic conditions prevail. At a radius of nearly 5 AU, the object becomes a protostar, and at 2000 K molecular hydrogen dissociates providing a second collapse.
Kade Rystalmane
Well-known member
Which notes? What is the context of these notes?
inertia
Super Member
Kade Rystalmane
Well-known member
And these statements from the book were observations taken over time?
inertia
Super Member
I was able to find many measurements dating back to 1987 and '88 and studies continue to this day.
B335 is considered an ideal protostellar core because it is free from a variety of large molecular cloud complexes and other nearby protostars. It makes an excellent natural laboratory for testing simple models.
Kade Rystalmane
Well-known member
Could you explain how these measurements show that the Bok Globules were at one point not stars and then became stars?
Kade Rystalmane
Well-known member
I'd like to approach this from a different vector by addressing some known physics.
1. Gasses expand to fill available space.
2. Nebulae are gasses that are many light years across and very sparse (10^3 particles/cu cm) and cold (~100K).
3. As gasses are condensed, pressure increases, making them "want" to expand even moreso.
4. Gravity is by far the weakest of forces (G = 6.67x10^(-11) and is diminished by the inverse square law (1/d^2).
5. Electromagnetism is 134 quadrillion times stronger than gravity (k_e = 9.00x10^9) and is also diminished by the inverse square law (1/d^2).
6. Nebulae are said to be formed by a rapidly expanding (exploding) star (supernova).
Knowing these things, why would we conclude that these sparse gases ever could or would contract into a star? I suggest to you that the amount of time we have been observing nebulae and alleged "protostars" has been far too short to make direct observational measurements necessary to come to the conclusion that new stars form. I suggest that much of what is alleged about new star formation is conjecture rather than necessary inference from observation of nature. While a process has been hypothesized, there has been no meaningful testing of the hypothesis other than computer models which alone are insufficient to show anything other than the conjectures in action.
1. Gasses expand to fill available space.
2. Nebulae are gasses that are many light years across and very sparse (10^3 particles/cu cm) and cold (~100K).
3. As gasses are condensed, pressure increases, making them "want" to expand even moreso.
4. Gravity is by far the weakest of forces (G = 6.67x10^(-11) and is diminished by the inverse square law (1/d^2).
5. Electromagnetism is 134 quadrillion times stronger than gravity (k_e = 9.00x10^9) and is also diminished by the inverse square law (1/d^2).
6. Nebulae are said to be formed by a rapidly expanding (exploding) star (supernova).
Knowing these things, why would we conclude that these sparse gases ever could or would contract into a star? I suggest to you that the amount of time we have been observing nebulae and alleged "protostars" has been far too short to make direct observational measurements necessary to come to the conclusion that new stars form. I suggest that much of what is alleged about new star formation is conjecture rather than necessary inference from observation of nature. While a process has been hypothesized, there has been no meaningful testing of the hypothesis other than computer models which alone are insufficient to show anything other than the conjectures in action.
Congratulations, you have just proved the sun is not possible - it is basically just hydrogen under pressure.
Either that, or your hypothesis is faulty.
Kade Rystalmane
Well-known member
Expanding gasses from an exploded star reversing direction under these conditions to form new stars is a different scenario than a star that already exists and is burning through its fuel. These aren't the same conditions and so we can't reject or accept the one based on the other.
I'm asking for hard evidence for star formation here, and so far inertia is the only one willing to engage on an academic level (which I greatly appreciate).
Nevertheless, your objections apply to the sun. It is a huge mass of hydrogen under extreme pressure. If you are right, those gases will quickly dissipate.
The gas giants are other examples. They are virtually all hydrogen, and some how the gravity is strong enough to keep the hydrogen there.
In fact, just on Earth, we have air around us that is held here by this incredibly weak force - gravity.
inertia
Super Member
Definitions are important. A bok globule is a small dark nebula.
Measurements since 1987 show that the protostar within B335 is currently collapsing, but not at a "freefall rate". More recently, organic molecules have been discovered within a compact region around 10 AU of the core. The source is from a carbon chain reaction, a well-known nuclear process.
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Kade Rystalmane
Well-known member
Again, these are not the same conditions and scenarios. Yes, those statements do apply in context, but a giant gas cloud spread over light years is not comparable to a thin layer (approximately 100km thick) of atmosphere attracted to the earth which has a radius of ~6371km and a mass that is more than a million times greater. The atmospheric pressure is insufficient to generate enough velocity in the majority of the atmosphere and only those at the very top have enough energy and velocity to reach escape velocity at all.
This can be applied to the gas giants and stars as well. Their radii (which matters more than mass) are comparatively small and so the inverse square law demands that gravity be relatively strong in these cases, strong enough to hold those gasses under pressure from escaping except for small amounts at the surface.
Nebulae, on the other hand, are a different kind of body altogether. The radius is extremely large compared to the overall mass of the cloud and the pressure is more than sufficient to cause expansion in spite of gravity. In fact, if you look at what is observed with regard to nebulae, they are all expanding. This is basic astronomy and is directly observable.
Kade Rystalmane
Well-known member
So from 1987 to 2021, observations show that this non-star, non-nebula celestial body has transformed from or into something else?
inertia
Super Member
- ...
In B335, the molecular gas is in fact collapsing with a developing magnetic field as predicted. Refinements in models are also upgraded in their precision as additional studies are conducted.
Answering your question above:
- We know because predictions concerning protostar physics are confirmed and refined with measurements.
At the other end of stellar lifetimes, a core-collapse was recently observed forming a black hole.
........
Reference: Astronomy
In B335, the molecular gas is in fact collapsing with a developing magnetic field as predicted. Refinements in models are also upgraded in their precision as additional studies are conducted.
Answering your question above:
- We know because predictions concerning protostar physics are confirmed and refined with measurements.
At the other end of stellar lifetimes, a core-collapse was recently observed forming a black hole.
........
Reference: Astronomy