The 3 types of energy stored within every atom
Chemical energy, where electrons transition in atoms, powers the reactions we see. But two other types hold more promise than all the rest.
This artist's illustration shows an electron orbiting an atomic nucleus, where the electron is a fundamental particle but the nucleus can be broken up into still smaller, more fundamental constituents. The simplest atom of all, hydrogen, is an electron and a proton bound together. Other atoms have more protons in their nucleus, with the number of protons defining the type of atom we're dealing with. Electrons, quarks, and gluons are presently thought to be fundamental, but surprises could yet await us on yet-to-be-probed, smaller subatomic scales.
(Credit: Nicole Rager Fuller/NSF)
Key Takeaways
- Atoms make up everything we’re familiar with in our world: electrons bound to atomic nuclei.
- The ways atoms bind together and electrons move to various energy levels absorb and release energy, accounting for most of the transitions we see.
- But there are other forms of energy in there, too, and if we can safely harness them, it will change everything.
The humble atom is the fundamental building block of all normal matter.
The hydrogen atom, one of the most important building blocks of matter, exists in an excited quantum state with a particular magnetic quantum number. Even though its properties are well-defined, certain questions, like ‘where is the electron in this atom,’ only have probabilistically-determined answers. This specific electron configuration is shown for magnetic quantum number m=2. (Credit: BerndThaller/Wikimedia Commons)
Hydrogen, in which single electrons orbit individual protons, composes ~90% of all atoms.
The Pillars of Creation, found in the Eagle Nebula a few thousand light-years from Earth, display a set of towering tendrils of gas and dust that are part of an active star-forming region. Even 13.8 billion years into the universe, approximately 90% of all the atoms out there, by number, are still hydrogen. (Credit: NASA, ESA and the Hubble Heritage Team (STScI/AURA))
Quantum mechanically, electrons only occupy specific energy levels.
Hydrogen density plots for an electron in a variety of quantum states. While three quantum numbers could explain a great deal, ‘spin’ must be added to explain the periodic table and the number of electrons in orbitals for each atom. (Credit: PoorLeno at English Wikipedia)
Atomic and molecular transitions between those levels absorbs and/or releases energy.
Electron transitions in the hydrogen atom, along with the wavelengths of the resultant photons, showcase the effect of binding energy and the relationship between the electron and the proton in quantum physics. Hydrogen’s strongest transitions are ultraviolet, in the Lyman-seires (transitioning to n=1), but its second strongest transitions are visible: Balmer-series lines (transitions to n=2). (Credit: OrangeDog and Szdori/Wikimedia Commons)
Energetic transitions have many causes: photon absorption, molecular collisions, atomic bond breaking/forming, etc.
The energy level differences in an atom of Lutetium-177. Note how there are only specific, discrete energy levels that are acceptable. While the energy levels are discrete, the positions of the electrons are not. (Credit: M.S. Litz and G. Merkel Army Research Laboratory, SEDD, DEPG Adelphi, MD)
Chemical energy powers most human endeavors, through coal, oil, gas, wind, hydroelectric, and solar power.
Traditional power plants, based on the combustion reactions of fossil fuels, such as the Dave Johnson coal-fired power plant in Wyoming, can generate tremendous quantities of energy, but require the burning of an enormous quantity of fuel in order to do so. By comparison, nuclear transitions, rather than electron-based transitions, can be over 100,000 times as energy-efficient. (Credit: Greg Goebel/flickr)
The most energy-efficient chemical reactions convert merely ~0.000001% of their mass into energy.
One of the most efficient sources of chemical energy can be found in the application of rocket fuel: where liquid hydrogen fuel is combusted by burning in conjunction with oxygen. Even with this application, demonstrated here with the first launch of the Saturn I, Block II rocket from 1964, the efficiency is much, much lower than nuclear reactions are capable of achieving. (Credit: NASA/Marshall Space Flight Center)
However, atomic nuclei offer superior options.
Although, by volume, an atom is mostly empty space, dominated by the electron cloud, the dense atomic nucleus, responsible for only 1 part in 10^15 of an atom’s volume, contains ~99.95% of an atom’s mass. Reactions between internal components of a nucleus can release far more energy than electron transitions can. (Credit: Yzmo and Mpfiz/Wikimedia Commons)
Containing 99.95% of an atom’s mass, bonds between protons and neutrons involve significantly greater energies.
The Uranium-235 chain reaction that both leads to a nuclear fission bomb, but also generates power inside a nuclear reactor, is powered by neutron absorption as its first step, resulting in the production of three additional free neutrons. (Credit: E. Siegel, Fastfission/public domain)
Nuclear fission, for example, converts ~0.09% of the fissionable mass into pure energy.
The Palo Verde nuclear reactor, shown here, generates energy by splitting apart the nucleus of atoms and extracting the energy liberated from this reaction. The blue glow comes from emitted electrons streaming into the surrounding water, where they travel faster than light in that medium, and emit blue light: Cherenkov radiation. (Credit: Department of Energy/American Physical Society)
Fusing hydrogen into helium achieves even greater efficiencies.
The most straightforward and lowest-energy version of the proton-proton chain, which produces helium-4 from initial hydrogen fuel. Note that only the fusion of deuterium and a proton produces helium from hydrogen; all other reactions either produce hydrogen or make helium from other isotopes of helium. (Credit: Sarang/Wikimedia Commons)
For every four protons that fuse into helium-4, ~0.7% of the initial mass is converted into energy.
At the National Ignition Facility, omnidirectional high-powered lasers compress and heat a pellet of material to sufficient conditions to initiate nuclear fusion. A hydrogen bomb, where a nuclear fission reaction compresses the fuel pellet instead, is an even more extreme version of this, producing greater temperatures than even the center of the Sun. (Credit: Damien Jemison/LLNL)
Nuclear power universally outstrips electron transitions for energy efficiency.
Here, a proton beam is shot at a deuterium target in the LUNA experiment. The rate of nuclear fusion at various temperatures helped reveal the deuterium-proton cross-section, which was the most uncertain term in the equations used to compute and understand the net abundances that would arise at the end of Big Bang Nucleosynthesis. (Credit: LUNA Experiment/Gran Sasso)
Still, the atom’s greatest source of energy is rest mass, extractable via Einstein’s E = mc2.
The production of matter/antimatter pairs (left) from pure energy is a completely reversible reaction (right), with matter/antimatter annihilating back to pure energy. If a reliable, controllable source of antimatter were obtainable, the annihilation of antimatter with matter offers the most energy efficient reaction possible: 100%. (Credit: Dmitri Pogosyan/University of Alberta)
Matter-antimatter annihilation is 100% efficient, converting mass completely into energy.
In the main image, our galaxy’s antimatter jets are illustrated, blowing ‘Fermi bubbles’ in the halo of gas surrounding our galaxy. In the small, inset image, actual Fermi data shows the gamma-ray emissions resulting from this process. These “bubbles” arise from the energy produced by electron-positron annihilation: an example of matter and antimatter interacting and being converted into pure energy via E = mc^2. (Credit: David A. Aguilar (main); NASA/GSFC/Fermi (inset))
Practically unlimited energy is locked within every atom; the key is to safely and reliably extract it.
Just as an atom is a positively charged, massive nucleus orbited by one or more electrons, anti-atoms simply flip all of the constituent matter particles for their antimatter counterparts, with positron(s) orbiting the negatively-charged antimatter nucleus. The same energetic possibilities exist for antimatter as matter. (Credit: Katie Bertsche/Lawrence Berkeley Lab)
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.
