Is it possible to convert mass into energy

Such interactions happen to gamma rays again and again and again as they make their way slowly toward the outer layers of the Sun, until their energy becomes so reduced that they are no longer gamma rays but X-rays recall what you learned in The Electromagnetic Spectrum.

Later, as the photons lose still more energy through collisions in the crowded center of the Sun, they become ultraviolet photons. Figure 5. Proton-Proton Chain, Step 2: This is the second step of the proton-proton chain, the fusion reaction that converts hydrogen into helium in the Sun. This step combines one hydrogen nucleus, which is a proton shown in blue , with the deuterium nucleus from the previous step shown as a red and blue particle.

The product of this is an isotope of helium with two protons blue and one neutron red and energy in the form of gamma-ray radiation. To be precise, each gamma-ray photon is ultimately converted into many separate lower-energy photons of sunlight. The length of time that photons require to reach the surface depends on how far a photon on average travels between collisions, and the travel time depends on what model of the complicated solar interior we accept.

Estimates are somewhat uncertain but indicate that the emission of energy from the surface of the Sun can lag its production in the interior by , years to as much as 1,, years. Figure 6. Proton-Proton Chain, Step 3: This is the third step in the fusion of hydrogen into helium in the Sun. Note that the two helium-3 nuclei from the second step see Figure 5 must combine before the third step becomes possible.

The two protons that come out of this step have the energy to collide with other protons in the Sun and start step one again. In addition to the positron, the fusion of two hydrogen atoms to form deuterium results in the emission of a neutrino. Neutrinos move at nearly the speed of light, and they escape the Sun about two seconds after they are created. The second step in forming helium from hydrogen is to add another proton to the deuterium nucleus to create a helium nucleus that contains two protons and one neutron Figure 5.

In the process, some mass is again lost and more gamma radiation is emitted. Such a nucleus is helium because an element is defined by its number of protons; any nucleus with two protons is called helium. That helium has two neutrons and two protons and hence is called helium-4 4 He.

To get to helium-4 in the Sun, helium-3 must combine with another helium-3 in the third step of fusion illustrated in Figure 6. Note that two energetic protons are left over from this step; each of them comes out of the reaction ready to collide with other protons and to start step 1 in the chain of reactions all over again.

The nuclear reactions in the Sun that we have been discussing can be described succinctly through the following nuclear formulas:. Note that the third step requires two helium-3 nuclei to start; the first two steps must happen twice before the third step can occur. Although, as we discussed, the first step in this chain of reactions is very difficult and generally takes a long time, the other steps happen more quickly.

After the deuterium nucleus is formed, it survives an average of only about 6 seconds before being converted into 3 He. About a million years after that on average , the 3 He nucleus will combine with another to form 4 He.

We can compute the amount of energy these reactions generate by calculating the difference in the initial and final masses. The masses of hydrogen and helium atoms in the units normally used by scientists are 1. Here, we include the mass of the entire atom, not just the nucleus, because electrons are involved as well. When hydrogen is converted into helium, two positrons are created remember, the first step happens twice , and these are annihilated with two free electrons, adding to the energy produced.

The mass lost, 0. Thus, if 1 kilogram of hydrogen is converted into helium, then the mass of the helium is only 0. This amount, the energy released when a single kilogram 2. As large as these numbers are, the store of hydrogen and thus of nuclear energy in the Sun is still more enormous, and can last a long time—billions of years, in fact. At the temperatures inside the stars with masses smaller than about 1.

In the proton-proton chain, protons collide directly with other protons to form helium nuclei. In hotter stars, another set of reactions, called the carbon-nitrogen-oxygen CNO cycle, accomplishes the same net result. In the CNO cycle , carbon and hydrogen nuclei collide to initiate a series of reactions that form nitrogen, oxygen, and ultimately, helium. The nitrogen and oxygen nuclei do not survive but interact to form carbon again. Therefore, the outcome is the same as in the proton-proton chain: four hydrogen atoms disappear, and in their place, a single helium atom is created.

The CNO cycle plays only a minor role in the Sun but is the main source of energy for stars with masses greater than about the mass of the Sun. So you can see that we have solved the puzzle that so worried scientists at the end of the nineteenth century. The Sun can maintain its high temperature and energy output for billions of years through the fusion of the simplest element in the universe, hydrogen. As will be discussed in the following chapters, we can define a star as a ball of gas capable of getting its core hot enough to initiate the fusion of hydrogen.

There are balls of gas that lack the mass required to do this Jupiter is a local example ; like so many hopefuls in Hollywood, they will never be stars. We have already duplicated it in an uncontrolled way in hydrogen bombs, but we hope our storehouses of these will never be used. Water is much more evenly distributed around the world than oil or uranium, meaning that a few countries would no longer hold an energy advantage over the others.

And unlike fission, which leaves dangerous byproducts, the nuclei that result from fusion are perfectly safe. The problem is that, as we saw, it takes extremely high temperatures for nuclei to overcome their electrical repulsion and undergo fusion. Interactions at such temperatures are difficult to sustain and control.

To make fusion power on Earth, after all, we have to do what the Sun does: produce temperatures and pressures high enough to get hydrogen nuclei on intimate terms with one another. The facility is being built in France. Construction will require over 10,, components and workers for assembly. The date for the start of operations is yet to be determined. ITER is based on the Tokamak design, in which a large doughnut-shaped container is surrounded by superconducting magnets to confine and control the hydrogen nuclei in a strong magnetic field.

Previous fusion experiments have produced about 15 million watts of energy, but only for a second or two, and they have required million watts to produce the conditions necessary to achieve fusion. The goal of ITER is to build the first fusion device capable of producing million watts of fusion energy for up to seconds.

The challenge is keeping the deuterium and tritium—which will participate in fusion reactions—hot enough and dense enough, for a long enough time to produce energy. Figure 7. ITER Design: The bright yellow areas in this model show where the superconducting magnets will circle the chamber within which fusion will take place.

A huge magnet will keep the charged nuclei of heavy hydrogen confined. The goal is to produce megawatts of energy. Solar energy is produced by interactions of particles—that is, protons, neutrons, electrons, positrons, and neutrinos.

The series of reactions required to convert hydrogen to helium is called the proton-proton chain. A helium atom is about 0. There's a book! It's a collection of over fifty of my favorite articles, revised and updated.

It's interesting. It's good. You should buy it. Click the photo for a link to the amazon page, or this link for the ebook. Email Address. Skip to content. Home About Faq. Q: If you are talking to a distant alien, how would you tell them which way is left and which way is right?

Q: Would it be possible in the distant future to directly convert matter into energy? Posted on February 10, by The Physicist. Email Print Facebook Reddit Twitter. Bookmark the permalink. Myrddin Emrys says:. February 10, at pm. The Physicist says:. Tim Anderson says:. Will says:. February 11, at am. Alexander Cooke says:. February 24, at pm. June 13, at pm.

June 17, at pm. June 18, at am. Kovar Nosra says:. February 27, at pm. Micah Dameron says:. November 25, at am. Great article Physicist. November 26, at am. November 26, at pm. Stephen Simpson says:. September 29, at pm. Kharn says:. Made up of three quarks apiece, each nucleon in an atomic nucleus is held together by gluons exchanged between these quarks: a spring-like force that gets stronger the farther apart the quarks get. The reason that protons have a finite size, despite being made of point-like particles, is because of the strength of this force and the charges-and-couplings of the particles inside the atomic nucleus.

The strong force, operating as it does because of the existence of 'color charge' and the exchange At ultra-high energies, such as in the very early Universe or in heavy ion colliders like RHIC or at the LHC, these conditions have been achieved, creating a quark-gluon plasma. Once the temperatures, energies and densities drop to low enough values, however, the quarks become re-confined, and that's where the majority of normal matter's mass comes from.

In other words, it's far less energetically favorable to have three free quarks — even with the non-zero rest massive given to them by the Higgs — than it is to have those quarks bound together into composite particles like protons and neutrons. The majority of the energy E responsible for the known masses m in our Universe comes from the strong force, and the binding energy introduced by the quantum rules governing particles with a color-charge. The three valence quarks of a proton contribute to its spin, but so do the gluons, sea quarks and The electrostatic repulsion and the attractive strong nuclear force, in tandem, are what give the proton its size, and the properties of quark mixing are required to explain the suite of free and composite particles in our Universe.

The sum of the different forms of binding energy, along with the quarks' rest mass, is what gives mass to the proton and all atomic nuclei. What we all learned a long time ago is still true: energy can always be converted from one form to another.

But this occurs only at a cost: the cost of pumping enough energy into a system in order to eliminate that additional form of energy. For kinetic energy example earlier, that meant boosting either your speed as the observer or the particle's speed relative to you, the observer until they match, both of which require the input of energy. For other forms of energy, it can be more complex. Gravitational potential energy, resulting from the deformation of space due to a mass, also plays a role.

Even planet Earth, as a whole, is about 0. Instead of an empty, blank, three-dimensional grid, putting a mass down causes what would have been The curvature of space due to the gravitational effects of Earth is one visualization of gravitational potential energy, which can be enormous for systems as massive and compact as our planet.

Only by destroying the object entirely — either by colliding it with antimatter causing the release of energy or pumping enough energy into it for composite particles only, leaving its fundamental constituents intact — can we convert that mass back into energy of some form. For the fundamental particles of the Standard Model, the Higgs field and its coupling to each of those particles provides the energy that makes up the mass, m.

But for the majority of the known mass in the Universe, protons, neutrons, and other atomic nuclei, it's the binding energy that arises from the strong force that gives us most of our mass, m.

For dark matter? Nobody yet knows, but it could be the Higgs, some form of binding energy, or something else entirely novel. Whatever the cause, however, something is providing the energy for this unseen mass. This is a BETA experience. You may opt-out by clicking here. More From Forbes. Nov 10, , pm EST. Nov 9, , pm EST.