What is darkness made of

What is the origin of light elements? It appears that the most plausible origin is nucleosynthesis in the big bang for the lighter ones, and spallation induced by galactic cosmic rays in interstellar space for the heavier ones.

What can light do? The speed of the wave is equal to the product of the wavelength and the frequency. So, light is a wave. This means that it has all the above properties and can do wavey things such as: Expand and radiate in all directions like a lightbulb or the waves in the water caused by a rock.

Is dark matter antimatter? Although the names sound vague and almost fictional, the types of matter called antimatter, dark matter, dark energy, and degenerate matter are all different, specific entities that really exist in our universe. Antimatter is just regular matter with a few properties flipped, such as the electric charge. What is darkness made of? Most scientists think that dark matter is composed of non-baryonic matter.

The lead candidate, WIMPS weakly interacting massive particles , have ten to a hundred times the mass of a proton, but their weak interactions with "normal" matter make them difficult to detect. Are black holes dark matter? They are naturally a good dark matter candidate: they are nearly collision-less and stable if sufficiently massive , they have non-relativistic velocities, and they form very early in the history of the Universe typically less than one second after the Big Bang.

Are humans made of energy? In life, the human body comprises matter and energy. That energy is both electrical impulses and signals and chemical reactions. The same can be said about plants, which are powered by photosynthesis, a process that allows them to generate energy from sunlight. What is the universe made of? The Universe is composed almost completely of dark energy, dark matter, and ordinary matter.

Other contents are electromagnetic radiation estimated to constitute from 0. Their size and mass, along with their rich reserves of dark matter, make galaxy clusters valuable cosmic laboratories for the study of the properties of the whole Universe.

More on galaxy clusters. Missing Baryons Astronomers have known for some time that about half of all of the baryonic matter, a.

One idea is that these missing baryons became part of an extremely diffuse web-like system of gas clouds from which galaxies and clusters of galaxies formed. One of the best ways to detect these missing baryons is through their faint, but observable, X-ray signatures. Our Universe Astronomers use every appropriate means at their disposal to investigate the biggest questions in the Universe.

In the past decade, Chandra has demonstrated tahat X-rays are a fundamental part of the modern astronomer's toolkit. Many wavelengths. One Universe. There are many possible calculations, but this is one:.

How big is a jelly bean? A typical jelly bean would measure about 2 cm long by about 1. Do jelly beans completely fill the container? The number of jelly beans is the occupied volume of the container divided by the volume of a single jelly bean. The volume of one jelly bean is approximated by the volume of a small cylinder 2 cm long and 1. Understanding cosmic distance to a supernova remnant Students work with a photograph to determine its scale and the time taken by light and matter to reach a specified distance.

Perhaps the most significant sign of the existence of dark matter, however, is our very existence. Despite its invisibility, dark matter has been critical to the evolution of our universe and to the emergence of stars, planets and even life. That is because dark matter carries five times the mass of ordinary matter and, furthermore, does not directly interact with light. Both these properties were critical to the creation of structures such as galaxies—within the relatively short time span we know to be a typical galaxy lifetime—and, in particular, to the formation of a galaxy the size of the Milky Way.

Without dark matter, radiation would have prevented clumping of the galactic structure for too long, in essence wiping it out and keeping the universe smooth and homogeneous.

The galaxy essential to our solar system and our life was formed in the time since the big bang only because of the existence of dark matter. Some people, on first hearing about dark matter, feel dismayed. How can something we do not see exist?

At least since the Copernican revolution, humans should be prepared to admit their noncentrality to the makeup of the universe.

Yet each time people learn about it in a new context, many get confused or surprised. There is no reason that the matter we see should be the only type of matter there is. The existence of dark matter might be expected and is compatible with everything we know. Perhaps some confusion lies in the name.

Dark matter should really be called transparent matter because, as with all transparent things, light just passes through it. Nevertheless, its nature is far from transparent. Physicists and astronomers would like to understand, at a more fundamental level, what exactly dark matter is. Is it made up of a new type of fundamental particle, or does it consist of some invisible, compact object, such as a black hole?

If it is a particle, does it have any albeit very weak interaction with familiar matter, aside from gravity? Does that particle have any interactions with itself that would be invisible to our senses? Is there more than one type of such a particle? Do any of these particles have interactions of any sort?

My theoretical colleagues and I have thought about a number of interesting possibilities.