- #1
SpikeVoyager
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Can I microscopic solar system exist out in space somewhere? Can a miniature sun exist? Can there be life on it if it exists?
Can a microscopic solar system exist?
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Discussion Overview
The discussion revolves around the feasibility of a microscopic solar system existing in space, including the possibility of a miniature sun and the implications for life within such a system. The scope includes theoretical considerations of gravitational stability, the requirements for nuclear fusion, and the conditions necessary for life.
Discussion Character
- Exploratory
- Debate/contested
- Conceptual clarification
Main Points Raised
- Some participants suggest that a scaled-down solar system could be gravitationally stable over billions of years, assuming a Newtonian framework, but question the likelihood of such a system existing given the universe's complexity.
- There is a minimum mass required for a star to undergo nuclear fusion, approximately 0.08 times that of the Sun, leading to the assertion that a miniature sun could exist if it is around 10% of the Sun's mass.
- One participant argues that the gravitational force would be too weak in a microscopic system to maintain stable orbits for planets, as gravitational force is directly proportional to the mass of the bodies involved.
- Another participant challenges the assertion that light is necessary for life, citing examples of organisms that thrive in complete darkness, such as those found in caves or near hydrothermal vents, suggesting that life could exist on rogue planets with internal heat sources.
- There is a debate over the necessity of light for life, with some asserting that usable energy sources, rather than light, are sufficient for life forms, while others maintain that light is essential for most known life forms.
- A participant states that physics prohibits self-gravitating hydrogen fusion for stars with masses less than 20 times that of Jupiter, arguing that this renders the discussion about miniature suns irrelevant.
Areas of Agreement / Disagreement
Participants express multiple competing views regarding the existence of a microscopic solar system, the requirements for life, and the conditions under which a miniature sun could exist. The discussion remains unresolved with no consensus reached.
Contextual Notes
Participants highlight various assumptions, such as the reliance on Newtonian physics versus general relativity, and the definitions of life and energy sources, which remain open to interpretation and debate.
- #2
Nereid
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Welcome to Physics Forums SpikeVoyager!
If there were nothing else in the universe, a system of cold bodies in the same mass ratios as the Sun and 8 planets, scaled down by many OOM (orders of magnitude) would likely be stable, gravitationally, over billions of years (assuming a Newtonian, not GR, universe). Of course, the orbits would be rather different in size - would you like to do a rough calculation to see how much different?
However, the universe is full of things other than our imaginary minature (cold) solar system, so I rather doubt there could be one. Interesting question though ... at various size scales, what would be the dominant physical processes that would disrupt a tiny solar system? Care to think this one through?
A 'sun' shines by nuclear fusion in its core ... there is a minimum mass for this, approx 0.08 that of our Sun. So if 'minature' means ~10% of ours, then there could be one, but not smaller.
And that pretty much answers the life question too ... while autotrophs may be quite common, 'life' as we usually think of it depends on photosynthesis, which requires a nice source of light. Looks like the answer to your general question is 'no'.
If there were nothing else in the universe, a system of cold bodies in the same mass ratios as the Sun and 8 planets, scaled down by many OOM (orders of magnitude) would likely be stable, gravitationally, over billions of years (assuming a Newtonian, not GR, universe). Of course, the orbits would be rather different in size - would you like to do a rough calculation to see how much different?
However, the universe is full of things other than our imaginary minature (cold) solar system, so I rather doubt there could be one. Interesting question though ... at various size scales, what would be the dominant physical processes that would disrupt a tiny solar system? Care to think this one through?
A 'sun' shines by nuclear fusion in its core ... there is a minimum mass for this, approx 0.08 that of our Sun. So if 'minature' means ~10% of ours, then there could be one, but not smaller.
And that pretty much answers the life question too ... while autotrophs may be quite common, 'life' as we usually think of it depends on photosynthesis, which requires a nice source of light. Looks like the answer to your general question is 'no'.
- #3
Fookie
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i don't think so...coz the gravitaional force which in turn provides centripetal foce around the orbit wud be too SMALLL!
remeber that grav. forc is directly proportinal to the product of the mass of two bodies...if mass is small then so is the grav. force.
if grav force is small then so is (mv2)/r.....so the planets wud not b able to maintain a circular orbit
remeber that grav. forc is directly proportinal to the product of the mass of two bodies...if mass is small then so is the grav. force.
if grav force is small then so is (mv2)/r.....so the planets wud not b able to maintain a circular orbit
- #4
JV
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I don't think that's true. Life (as we know it) needs liquid water, light is not needed. In caves and at the bottom of the ocean there are a lot of living creatures, and they don't get any light.Nereid said:Welcome to Physics Forums SpikeVoyager!
And that pretty much answers the life question too ... while autotrophs may be quite common, 'life' as we usually think of it depends on photosynthesis, which requires a nice source of light. Looks like the answer to your general question is 'no'.
So in theory live could exist on a rogue planet. As long as it has a hot core, for pockets of liquid water under the surface.
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Nereid
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Clarification: 'autotroph' is a general term, and includes plants; what I was thinking of is chemolithoautotrophs, what the 'red tubey things' found near undersea black smokers use as a source of energy, for example. AFAIK, all eukaryotes which live in caves are part of an ecosystem which ultimately depends upon plants and sunlight; those near black smokers ultimately depend either on the Sun or chemolithoautotrophic bacteria. Whether the latter alone can support a complex web of life is an open question today.JV said:
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- #6
quantumdude
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JV said:
Yes, it is needed. Water is not a source of energy for lifeforms (unless you can think of a lifeform that metabolizes by nuclear fusion).
- #7
Twistedseer
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vent life
http://nationalzoo.si.edu/Publications/ZooGoer/1996/3/lifewithoutlight.cfm
No Tom, all that is needed is a usable form of energy.
http://nationalzoo.si.edu/Publications/ZooGoer/1996/3/lifewithoutlight.cfm
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- #8
Chronos
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You can forget about the miniature suns. Physics forbids self gravitating hydrogen fusion unless the mass of the candidate star is at least 20x the mass of Jupiter. The rest of your argument is, therefore, irrelevant.
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