DARK MATTER

Dark Matter –The Cosmos

What is dark matter? This apparently invisible and mysterious stuff that researchers think is everywhere is not easily understood. A first step, however, is grasping what can be seen, and why.

When a scientist observes the space, either through a standard telescope or with the aid of a space-based observatory the things she observes emit light energy, called electromagnetic radiation.

Some of this radiation is optical — the visible light you see with your eyes. But this is just one type of light energy. Electromagnetic radiation comes in many wavelengths: radio waves (the longest), infrared, optical, ultraviolet, X-Rays and short gamma rays (the shortest, and also the highest form of energy. See more details on these wavelengths at the bottom of this page).

Galaxies, nebulae, stars, trees, microscopic bugs and anything else that can be observed glows with energy at one of these wavelengths.

But in recent decades, researchers have become increasingly convinced that there is a vast amount of material in the universe that does not glow at all. This mysterious “dark matter” is believed by most scientists to be the most common stuff in the universe, perhaps making up 90 percent or more of the total mass

Dark matter does not emit enough energy to be directly detected. But indirectly, researchers note its presence. Anything that has a mass exerts the force that we call gravity. Dark matter — or something that we have yet to find — exerts a gravitational pull on objects in and around distant galaxies, and even on light emitted by those objects, say scientists at NASA’s Goddard Space Flight Center.

By measuring these mysterious effects of gravity, researchers determine how much “extra” gravity is present, and hence how much extra mass, or dark matter, must exist.

In large clusters of galaxies, for example, scientists say that five to 10 times more material exists than can be accounted for by the stars and gas they find.

So what is dark matter made of? No one knows for sure.

Normal matter — you, your computer and the air you breathe — is made of atoms, which are composed of protons, neutrons and electrons. Scientists call this “baryonic” matter. They suspect some dark matter is of the normal, baryonic variety. This might include brown dwarf stars and other objects that are simply too small, or too dim, to be seen from great distances.

But most dark matter is thought to be non-baryonic — truly strange.

If this is true, then just finding the stuff will be difficult, because researchers don’t even know what they are looking for.

lengths of light (Electromagnetic radiation

• Radio: Wavelengths longer than infrared and very low energy.
• Infrared: Wavelengths longer than the red end of visible light and shorter than microwaves (roughly between 1 and 100 microns). Little infrared radiation reaches Earth’s surface, but some can be observed by high-altitude aircraft or telescopes on tall mountains.
• Optical/Visible: Electromagnetic radiation at wavelengths visible to the human eye. We perceive this radiation as colors ranging from red (longer wavelengths about 700 nanometers) to violet (shorter wavelengths about 400 nanometers).
• Ultraviolet: Wavelengths shorter than the violet end of visible light. Earth’s atmosphere blocks most ultraviolet light.
• X-rays: Very short wavelengths and very high-energy; X-rays have shorter wavelengths than ultraviolet light but longer wavelengths than gamma rays.
• Gamma rays: The highest energy, shortest wavelength electromagnetic radiation. Usually, they are thought of as any photons having energies greater than about 100 keV (kiloelectron volts).

 

Conclusion

And now  if we are an open mind we may think of even anothers forms of light energy and mass that leaves us to believe that all we know is still the beginning of understanding  the universe and all the tranformations that can be done.

Adapted and added  from Light and energy by jmvc