[profound (OP)]

The disadvantage of chemical sensors is you can never be sure weather it is chemical or biological in nature as explained above.

That's wrong on two counts.
You need to learn to spell "whether".
But much more importantly, the chemical clues are not- as you imply- specific to any particular life form.
Do you understand that any disequilibrium indicates the presence of life (or, at least- something weird).
For example, the Earth's atmosphere contains oxygen and also methane.
Over geological time the two compounds should have reacted.
Yet they are still both there.
It doesn't tell you where the two gases come from- but it does tell you that something is making at least one of them continuously.
Maintaining a non- equilibrium system is strong evidence of life.
The clever bit is that you can look at the atmosphere (or water etc) anywhere on the planet and find the evidence.
You don't have to tak a zillion samples of teh surface then carefully microtome them and mount them on slides so you can put them through an automated microscope and then search for heaven knows what because we don't know what a Martian looks like.
It's really bloody clever.
The guys at NASA are good at thinking of clever tricks like that.

Am I right in thinking you didn't understand that before?

But you can never tell where the methane came from. Was it a life byproduct or chemical reactions.

You argument about a what a martian looks like is absurd.when the microscope was first invented no one knew what bacteria looked like.

[Bored chemist]

The disadvantage of chemical sensors is you can never be sure weather it is chemical or biological in nature as explained above.

That's wrong on two counts.
You need to learn to spell "whether".
But much more importantly, the chemical clues are not- as you imply- specific to any particular life form.
Do you understand that any disequilibrium indicates the presence of life (or, at least- something weird).
For example, the Earth's atmosphere contains oxygen and also methane.
Over geological time the two compounds should have reacted.
Yet they are still both there.
It doesn't tell you where the two gases come from- but it does tell you that something is making at least one of them continuously.
Maintaining a non- equilibrium system is strong evidence of life.
The clever bit is that you can look at the atmosphere (or water etc) anywhere on the planet and find the evidence.
You don't have to tak a zillion samples of teh surface then carefully microtome them and mount them on slides so you can put them through an automated microscope and then search for heaven knows what because we don't know what a Martian looks like.
It's really bloody clever.
The guys at NASA are good at thinking of clever tricks like that.

Am I right in thinking you didn't understand that before?

But you can never tell where the methane came from. Was it a life byproduct or chemical reactions.

You argument about a what a martian looks like is absurd.when the microscope was first invented no one knew what bacteria looked like.

Thanks for answering my question- albeit accidentally.
Even after I explained it,  you still don't understand it.

The point is that only life (of some sort) is a credible explanation for the disequilibrium.

to the extent to which this "You argument about a what a martian looks like is absurd.when the microscope was first invented no one knew what bacteria looked like." is true, we are taking it in turns to be absurd.
Do you understand that the microscopes that check chips know exactly what they are looking for (and are thus not the same as the first microscopes)?

It does not matter where the methane came from.
Something keeps making it (or it would have been destroyed)

Do you understand that?
If there's only oxygen- it might be what you call "chemical"  and what real scientists call abiotic.
If there's only methane, it might be abiotic.
But there's no way that an abiotic system produced both in a stable system.
Can you understand that?

[profound (OP)]

The disadvantage of chemical sensors is you can never be sure weather it is chemical or biological in nature as explained above.

That's wrong on two counts.
You need to learn to spell "whether".
But much more importantly, the chemical clues are not- as you imply- specific to any particular life form.
Do you understand that any disequilibrium indicates the presence of life (or, at least- something weird).
For example, the Earth's atmosphere contains oxygen and also methane.
Over geological time the two compounds should have reacted.
Yet they are still both there.
It doesn't tell you where the two gases come from- but it does tell you that something is making at least one of them continuously.
Maintaining a non- equilibrium system is strong evidence of life.
The clever bit is that you can look at the atmosphere (or water etc) anywhere on the planet and find the evidence.
You don't have to tak a zillion samples of teh surface then carefully microtome them and mount them on slides so you can put them through an automated microscope and then search for heaven knows what because we don't know what a Martian looks like.
It's really bloody clever.
The guys at NASA are good at thinking of clever tricks like that.

Am I right in thinking you didn't understand that before?

But you can never tell where the methane came from. Was it a life byproduct or chemical reactions.

You argument about a what a martian looks like is absurd.when the microscope was first invented no one knew what bacteria looked like.

Thanks for answering my question- albeit accidentally.
Even after I explained it,  you still don't understand it.

The point is that only life (of some sort) is a credible explanation for the disequilibrium.

to the extent to which this "You argument about a what a martian looks like is absurd.when the microscope was first invented no one knew what bacteria looked like." is true, we are taking it in turns to be absurd.
Do you understand that the microscopes that check chips know exactly what they are looking for (and are thus not the same as the first microscopes)?

It does not matter where the methane came from.
Something keeps making it (or it would have been destroyed)

Do you understand that?
If there's only oxygen- it might be what you call "chemical"  and what real scientists call abiotic.
If there's only methane, it might be abiotic.
But there's no way that an abiotic system produced both in a stable system.
Can you understand that?

Now you are being absurd again.do chemical systems stay the same over time?.
you take a cup of water from the sea and its pure.have an hour later it contains toxins sludge from a factory due to currents.

The chemicals from the waste interact and produce new chemicals.is it due to life or chemistry?

Thus chemical analysis can never be definite.You failed to mention viking which were a joke due to interpretation.Just like religion.

[alancalverd]

You are a very rude and ignorant little boy, but as ignorance is excusable I will ask you once more to tell us what you think is the difference between life and other chemistry. BC has explained NASA's distinction very clearly.

[jeffreyH]

Any idiot can be a troll and gain a short term reward. To seek and actually find a truth isn't easy but gives long-term rewards. There are shortcuts. Read up on the past mistakes of others or just ask the right questions on this forum. It is a lot friendlier and more tolerant than some others. The senior members are invaluable sources of help with learning.

[Bored chemist]

The disadvantage of chemical sensors is you can never be sure weather it is chemical or biological in nature as explained above.

That's wrong on two counts.
You need to learn to spell "whether".
But much more importantly, the chemical clues are not- as you imply- specific to any particular life form.
Do you understand that any disequilibrium indicates the presence of life (or, at least- something weird).
For example, the Earth's atmosphere contains oxygen and also methane.
Over geological time the two compounds should have reacted.
Yet they are still both there.
It doesn't tell you where the two gases come from- but it does tell you that something is making at least one of them continuously.
Maintaining a non- equilibrium system is strong evidence of life.
The clever bit is that you can look at the atmosphere (or water etc) anywhere on the planet and find the evidence.
You don't have to tak a zillion samples of teh surface then carefully microtome them and mount them on slides so you can put them through an automated microscope and then search for heaven knows what because we don't know what a Martian looks like.
It's really bloody clever.
The guys at NASA are good at thinking of clever tricks like that.

Am I right in thinking you didn't understand that before?

But you can never tell where the methane came from. Was it a life byproduct or chemical reactions.

You argument about a what a martian looks like is absurd.when the microscope was first invented no one knew what bacteria looked like.

Thanks for answering my question- albeit accidentally.
Even after I explained it,  you still don't understand it.

The point is that only life (of some sort) is a credible explanation for the disequilibrium.

to the extent to which this "You argument about a what a martian looks like is absurd.when the microscope was first invented no one knew what bacteria looked like." is true, we are taking it in turns to be absurd.
Do you understand that the microscopes that check chips know exactly what they are looking for (and are thus not the same as the first microscopes)?

It does not matter where the methane came from.
Something keeps making it (or it would have been destroyed)

Do you understand that?
If there's only oxygen- it might be what you call "chemical"  and what real scientists call abiotic.
If there's only methane, it might be abiotic.
But there's no way that an abiotic system produced both in a stable system.
Can you understand that?

Now you are being absurd again.do chemical systems stay the same over time?.
you take a cup of water from the sea and its pure.have an hour later it contains toxins sludge from a factory due to currents.

The chemicals from the waste interact and produce new chemicals.is it due to life or chemistry?

Thus chemical analysis can never be definite.You failed to mention viking which were a joke due to interpretation.Just like religion.

And, once gain, you accidentally answer my question.
I asked "Can you understand that?"
And the answer is  clearly "no".