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Is there a way to extend or reduce the half-life of a radioactive object? Perhaps by subjecting it to more radiation or some other method.

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Increasing it's speed relative to the observer produces the appearance of a change in half-life, but no change in the rest frame. – AdamRedwine Jun 18 '12 at 12:15
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If you put your object in a nuclear reactor (for example) it can absorb a neutron and turn into a different isotope ("neutron capture"). It can also absorb very-high-energy-protons, etc. – Steve B Jun 18 '12 at 21:46

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Have a look at the paragraph "radioactive decay" .

The half life is characteristic of each radioactive nucleus and depends on the basic interactions holding the nucleus together.

It depends on the quantum mechanical probabilities of transition from one energy level to another, sometimes changing element in the periodic table.

Thus, to affect the half life, one would have to affect the basic interactions of the decay mechanism. There have been speculations on what would happen if the QFT vacuum is different, as in the Casimir effect, (a simpler explanation here), but I have not been able to find an experiment.

The simple answer is, no, the half life cannot change.

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Yes. It is true, as others have stated, that half-life, as such, is intrinsic and basically immutable. But, as you guessed, by bombarding it with further radiation, elements can be transmuted faster (and into different isotopes) than they would on their own. Also, elements that are not radioactive on their own can be transmuted this way.

A practical artifical version is neutron bombardment. This is proposed as a way of reducing nuclear waste, rather than waiting for centuries for it to decay on its own.

Neutrino bombardment also can do this. Even though there is no practical method to generate enough artifical neutrinos to cause transmutation, this does work as a practical method of detecting neutrinos from space.

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Yes there are independent variables for half life.

The electric charge of the radioisotope.

Also neutrino flux.

Edit: Say in the example of a radiotope that decays by electron capture you could in theory completely ionize electrons off the specie thus reducing the decay rate.

Or say focus a beam of nutrions from a neutrino gun upon some other radioisotope to reduce the half-life. Perhaps moving the source out of our earths atmosphere and closer to the sun would also have this effect.

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Your answer doesn't really address the OP's issues... maybe elaborate on what you mean a little bit? – Kitchi Dec 28 '12 at 11:59
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Your first example might be thought reasonable exept that it is extremely difficult to strip a high A nucleus from all its electrons. For you second, neutrinos are weakly interacting and neutral, so cannot be focused to a beam of the type you are imaging, and even if they were the probability of interacting with a nucleus to affect its decay probability is unmeasurably small: that is why they are called weak interactions. – anna v Dec 28 '12 at 14:03
I agree that these are not practical techniques but they are physical possibilities. In the first example even partial ionisation will reduce the decay rate. – UnkleRhaukus Dec 28 '12 at 15:42
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The Shnoll paper is junk science and was never published in a refereed journal. There is a cottage industry of kooks making bogus claims like this, the best known being Jenkins and Fischbach. – Ben Crowell Dec 28 '12 at 18:16
@BenCrowell Can you please explain how you can tell the Shnoll paper is junk? – UnkleRhaukus Dec 29 '12 at 2:06
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The simple answer is no, we can't change the half life. There's no technology available to us that can affect energy levels in the nucleus enough to make a change to the half life.

Having said that, I've always wondered if the Mossbauer effect could change the half life. Mossbauer spectroscopy measures tiny changes in the energy levels of nuclei due their chemical environment. If you can change the spacing of energy levels in a radioactive nucleus you could in principle change the probability of transition between them and therefore change the half life. However I've never heard of this effect being observed, and I suspect the shifts of energy levels would be too small to make any significant difference. You can only observe the shifts because Mossbauer spectroscopy is exquisitely sensitive.

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