Is there any evidence that atoms behave differently on other planets?

Question

I know gravity, atmosphere density and other values would be different on other planets, but is there any evidence that intrinsic atomic properties (i.e. melting point) are different on other planets?

Answer 1

There is no evidence that atoms behave any differently anywhere. To the best of our understanding physics works the same everywhere.

We obviously have little direct evidence to work with. We've sent a few rovers out to other planets, so we have indeed interacted directly with their atoms a bit. But we do have gobs of evidence from studying stars. We have found the behavior of stars to be astonishingly consistent with the studies we have been able to do on Earth.

The key example I would point to is the red shift. We noticed that the light from other galaxies was "red shifted" slightly. The spectrum of the individual atoms wasn't quite in the same place. We've determined that this can be explained by space expanding, and we've made some pretty good measurements as to how that red-shift is correlated to distance, known now as Hubble's Law.

If the physics on other starts was even a slight bit different, it would be unlikely that we would see results so astonishingly consistent that we could pick up these very slight effects.

Now, obviously there are some extrinsic effects. Things evaporate on Mars that don't evaporate on Earth because the Martian atmosphere is much much thinner. But I don't think those are the things you are talking about, and the evaporation rates are indeed consistent with what we observe on Earth if we pump a vacuum chamber down to Martian atmospheric pressures and observe the evaporation rates in the chamber.

Note: some of this is a sort of circular logic. Scientists are generally trying to find fundamental laws which are true for all places and all times, even other planets. Accordingly, we test our theories against what is known about other planets, and even send experiments out to learn more. The theories that remain after traversing this gauntlet of testing and consistency checking are the ones we point to and call "the laws of physics." As an engineer, we have plenty of laws which are Earth-specific. We're comfortable with using simpler laws which describe how things behave locally, because we need to build something large that needs to work. Only when we are taken out of our element (such as strapping a rocket to our devices and hurling them into space), are we forced to fall back on the more general laws that the physicists assert. For example, I've designed countless systems which were built on the simple rule that gravity was a force that pulled down with a magnitude of $9.8m/s^2$ for every kilogram of mass. That's a sufficient rule for my engineering. However, were I to design something that needed to go to Mars, I would have to recognize that this is insufficient. I'd have to use Newton's Universal Law of gravitation $F=\frac{GMm}{r^2}$ or maybe even a relativistic version of that equation. These are the equations that science has found are "true" everywhere we have ever looked.

Answer 2

There is absolutely no evidence that atoms behave differently on other planets, in fact, there is evidence to the contrary, in that many scientific instruments (with operating principles tied to atomic physics) have been operated in situ, either from or orbit or on the surface.

The SHARAD sounder relies on the polarizability of rock and ice (it sends radar deep into Mars). Neutron spectroscopy from orbit detects subsurface water on Mars. The laser and mass spectrometer on Mars Science Lab leverage atomic physics, from the surface. Any optical spectrometer (there are many) is probing atomic physics.

A comprehensive list would be...long.

Answer 3

Other answers already addressed some aspects of the universality of the laws of physics. I would just state that modern physcis theory is based on the fundamental concept that the laws of physics are the same for all observers, regardless of how they are moving or where they are relative to other observers. That's a core goal of relativity. We have found nothing to contradict that principle in observations of the cosmos.

is there any evidence that intrinsic atomic properties (i.e. melting point) are different on other planets

There is a misconception here.

Melting point (and boiling point) are not fixed values and can change as pressure and the structure of the material changes.

A good example is ice (i.e. solid water). The phase diagram for water shows that the melting point (the boundary between solid and liquid) is a line covering a range of temperatures from about $213\,K$ to extremely high temperatures ( the chart goes to about $475\,K$).

Like many materials water in solid form has many different structures depending on the conditions. Wikipedia lists a whole bundle of them here. The material can change between these forms as the pressure and temperature varies.

Intrinsic properties that would not change for atoms are the binding energies of electrons - and hence the spectral lines possible do not change, which is why spectrosopy is so important in astronomy. Again there is no evidence from observation that these values are different elsewhere in the universe - nothing inconsistent with the assumption they are fixed has been seen.

The diagram is from Wikipedia and is Creative Commons licensed.

Answer 4

The primary postulate in science is that if you observe a phenomenon in nature, under the same circumstances, you must observe that phenomenon again. If you find some fundamental forces and some physics' laws, we expect that you find them again anywhere else. This is the starting point of science and also the subject of some interesting arguments in philosophy of science since the time of Isaac Newton.

We anticipate nature works in this way and until now it has been working. No evidence have been found for different intrinsic atomic properties on other planets. Atoms are the building blocks of matter in our universe. At the macroscopic level, they have infinitly many manifestations.

Hope this helps.