Beyond What Our Eyes Can See

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Our Journey

Although the Universe is very, very big, its component parts are very, very small. Telescopes magnify and enhance the brightness of very distant big objects in our Universe, while microscopes magnify the smallest components of our Universe.


Refractor Telescope (American Institute of Physics) Sixty-foot (~18 meters) refractor telescope  Refracting telescopes reached imprac­tical lengths before being replaced by reflector telescopes. (Photo:

Telescopes that use glass lenses, which are similar to eye-glass lenses, are called refracting tele­scopes or re­fractors. To obtain larger and larger images, however, early refracting tele­scopes became longer and longer until impractical lengths of 20 or so meters (~60 feet) were attained. Convex Concave Lenses The first telescopes formed images with convex glass lenses, similar to the lenses used by eye doctors to correct for "far-sightedness"; concave lenses are used to correct for "near-sightedness" (Graphic by RBKOR). Yerkes refractor Although built in the early 1900s, the 40-inch (102-centimeter) Yerkes re­fracting telescope continues to operate. (Yerkes photo in public domain)

For telescopes to form bright images from very faint objects, lens diameters had to drastically increase. Grind­ing large-diameter glass lenses, however, has limitations, even with today's technology. The largest operating refracting telescope is the 40-inch (102-centimeter) refractor telescope at the Yerkes Observatory of the Uni­versity of Chicago.

Fortunately, during the early 1600s, several people had proposed the idea of a curved mirror that could enlarge celestial images. Later in the 1600s, Isaac Newton built a curved telescope mirror made of an alloy of tin and copper. Newton, consequently, is assigned the honor of being inventor of the reflector telescope.

Reflector Telescope  Reflector telescopes are now the mainstay of the large-telescope research arena. (Graphic by RBKOR)

One of the major advantages of modern reflector telescopes is that they produce sharper and less distorted images than refracting telescopes. Early, refracting telescopes produced halos of light around bright objects, much like what a person suffering from cataracts experiences. Today, small, multi-lens refracting telescopes can produce decent images, but refractors become more and more difficult to manufacture as they become larger and larger.  

Another reason for the popularity of reflector telescopes is that they are much smaller in size than an equivalent refracting telescope. Small, compact 10- or 12-inch reflector telescopes are quite powerful, yet light weight, and are popular among amateur astronomers.

Extending Our Vision

So far in this story, references to both refracting and reflector telescopes have focused solely on telescopes that can pass visible light. Visible light is defined as light that can be seen by the human eye.

The problem is that our eyes can see on­ly a tiny sliver of all the electromagnetic ra­diation (EMR) around us in our daily lives. Wavelengths outside of the range of 380 to 760 nanometers (nm) are invisible to us humans. Consequently, humans cannot see most of the EMR spectrum, for example: AM broadcast (300 meters), FM broadcast (3 meters), and the microwaves (about 12 centimeters) of our microwave ovens and cell phones, nor can we see X-rays (1 nanometer to 5 picometers), which are short enough to pass through molecules.

Only a sliver  Note about This Graphic: a collage by RBKOR of different images that were revised by numerous revisers from an original work published by NASA.

For us to see the world beyond visible light, we need special sensors to observe these non-visible wavelengths of light. A few household examples demonstrate some of the interactions between humans and invisible radiation.

Everyday Interactions with EMF

Wavelength (meters) and Frequency (Hz)
  • ⚬ 300 meters (or 1 megahertz; MHz):
     AM broadcast, marine navigation, marine com­munications;
  • ⚬ 1 meter (100 megahertz; MHz):
     FM broadcast, air traffic control, TV broadcast;
  • ⚬ 15 centimeters (2 gigahertz; GHz):
     Cell phones, GPS (global positioning system) microwave ovens, garage-door openers, com­puter central processors, radar, satellite com­munications;
  • ⚬ 500 nanometers (15 pitahertz; PHz):
     Visible light is sensed with eyes in animals and sensors in plants; several species in the animal kingdom see in infrared light (e.g. rattle snakes) and some insects see in ultraviolet light, e.g. honey bees;
  • ⚬ 1 nanometer (300 petahertz, PHz):
     X-ray machines in health care, non-destructive testing, fabrication of semi­conductor-ele­ments (e.g. transistors, ca­pacitors) form­ed on a silicon chip;
  • ⚬ 10 picometers [>3000 petahertz]:
    Uranium decay radiates from deep within Earth's interior, which drives ocean currents and volcanic activity, as well as, weather and other natural events.
    Nuclear power-plant fuel produces heat to make steam.
    Radio-active cobalt 60 emits radi­ation that kills cancer cells.
    PET scans (Positron* Emission Tomo­graphy; similar to CT x-ray scans): produce near-molecular-level images of pro­cesses in living tissue.
    Flying at 25,000 feet exposes passengers and crew to 500 times more cosmic radiation than exposure at ground level.
* Positrons are electrons that have a positive charge (e+, rather than the negative charge of electrons (e). When they collide with each other, they annihilate each other and emit smaller, sub-atomic particles, often also emitting gamma rays.

Nearly all of the Sun's visible light passes through our atmosphere, while many of the other wavelengths entering Earth's atmosphere are ab­sorbed by our upper atmosphere and never reach the Earth's surface. Ozone and floro-chloro hydro­carbons, as well as water vapor and methane (i.e. natural gas) all interact to shield the biosphere (lower atmosphere) from harmful "ionizing" radiation (radiation that removes electrons from an atom); for example, highly energetic ultraviolet rays, X-rays, gamma rays, and cosmic rays. Nearly all highly energetic EMR interacts with Earth's upper atmosphere. To fully understand how the Sun affects the Earth, we must look at the entire electromagnetic spectrum, rather than only the visible spectrum.

An aside: This author endures severe sunburn risk at the beech or in the countryside if not protected, but has anecdotally observed little sunburn in the city, also without protection. We can suggest a reason for this observation: air pollution from vehicles absorbs incoming ultraviolet light.

Prism: spectrum Specific wavelengths describe specific colors. For example: we "see" the color red when we see light about 680 nanometers; violet light is seen around 400 nanometers. Wave­lengths outside of the range of 0400–700 nm are invisible to us humans.

Thanks to modern tech­nology, we can see well-beyond our human vision. The entire spectrum of EMR (electromagnetic radiation) spans from very long wavelengths of thousands of kilo­meters to very, very short wavelengths of quadrillionths ( = 10−15) of a meter, which is the realm of sub-atomic par­ticles. Large, modern telescopes expand our vision far beyond visual light from long-wave radio EMR and infrared EMR to ultraviolet EMR, X-ray EMR, and to very energetic (very short wavelength) cosmic EMR emanating from our Sun and from other objects that lie deep in outer space.

The intensity of solar radiation varies over time periods of minutes to years and even centuries. Also, our Sun from time to time sporadically ejects massive amounts of high-energy particles that originate in solar magnetic storms. Solar magnetic storms have the potential to damage electric grids on a massive scale.

The Sun periodically displays patches of dark spots, called "sunspots", that vary in number from one cycle to another. Sunspot activity corresponds to periodic flipping of the Sun's magnetic poles as the sunspots rise and fall on a fairly regular schedule of 11 years.

Note: Earth's magnetic field also flips polarity in conjunction with the Sun's magnetic field flips.

The 11-year cycle from time-to-time, however, varies significantly in the length of particular cycles. When the Sun displays a large number of sunspots, long-distance low-frequency radio, Internet, and telephone communications suffer noise and interruptions, which is not good. On the other hand, heavy sunspot activity permits long-distance communications at the higher end of shortwave radio frequencies.

According to NASA (National Aero­nautics and Space Administration, US):

Although sunspots themselves produce only minor effects on solar emissions, the magnetic activity that accompanies the sunspots can produce dramatic changes in the ultraviolet and soft x-ray [weak x-rays] emission levels. These changes over the solar cycle have important conse­quences for the Earth's upper atmosphere.
  Marshall Space Flight Center, Solar Physics Branch

Researchers at Georgia State University correlate sunspot activity with the Earth's average temperature.  

…it is possible that the solar flare index and the sunspot observations are windows to subtle influences on the Earth's climate that we don't understand.
(Georgia State University: Hyper-Physics)
If this sunspot phenomenon does indeed parallel heating or cooling of Earth, we may very well have to remodel our long-term climate forecasting.

Note: with a projected decline in the Sun's future sunspot activity (NASA), a discussion will arise over the possibility of global cooling in the coming decade.

What Does This All Mean?

Most of the electromagnetic (EMR) spectrum cannot pass through our earth's atmosphere. Much of the radiation entering Earth's atmosphere is absorbed by Earth's upper atmosphere and does not reach our earthbound telescopes in the lower atmo­sphere. This phenomenon limits our earthly view of the Universe, as well as limiting our view of our earthly neighborhood.

As all of this electromagnetic radiation bombards our atmo­sphere, much of this incoming radiation is absorbed and is re-radiated as heat in the form of infrared radiation. A broad range of intensities of other wavelengths of light is also emitted.

The absorption charac­teristics of Earth's atmo­sphere moderate many of Earth's chem­ical, geologic, and weather systems. We might add that atmospheric ab­sorption characteristics are what make our sky appear blue; wavelengths cf blue light are absorbed a little less than the other visible wavelengths of light.

Plant spectrum Green plants absorb red and blue light, while reflecting green light. Graphic posted by Khan Academy and by OpenStax College, Biology (CC BY 3.0))

The chemical con­stituents of Earth's atmo­sphere also play a role in photosynthesis. If we compare the atmo­spheric absorption spectrum of visible light with the absorption spectrum of plant chlorophyll, we observe a nice fit at the long wavelengths (red) and at the short wavelengths (blue); plant chlorophyll absorbs red light and blue light, while reflecting green light. Leaves of plants, therefore, appear green to human eyes.

Any major change in the chemical composition of our atmosphere would have an impact on green plants. For example, a higher level of atmospheric oxygen would be bad for plants, while a higher level of atmospheric carbon dioxide would be good for plants. The entire universe, one can easily conjecture, is incredibly intertwined with the intertwining of its own constituents.

Viewing objects beyond our atmosphere has spurred creative scientists and engineers to design and build whole new families of telescopes that can capture high-resolution images of our Universe in many different wavelengths. Some of these "telescopes" are placed in Earth orbit, for example, the Hubble Orbiting Telescope, while other spacecraft orbit or flyby planets and the moons of planets, for example the Cassini Spacecraft orbiting Saturn.

The Cassini mission to Saturn was sponsored by 28 nations and was launched 15 October 1997. Cassini traveled 4.9 billion miles (7.9 billion kilometers) and sent back 635 gigabytes of data, granting Cassini the honor of being among the most extraordinary eyes in the sky before its programmed descent and subsequent crash into Saturn's surface on 25 September 2017, having operated a tad short of two decades.

Space-based telescope: Hubble Images recorded from the Hubble telescope have amazing clarity; the Andromeda Nebula was revealed by Hubble to be a galaxy. that is, the Andromeda Galaxy (NASA).

Another reason for deploying telescopes in space is that our atmo­sphere is con­tinually changing in density, hu­midity, tem­perature, and a few other more esoteric factors. A continually changing atmosphere distorts a telescope's image. Twinkling stars are the result of this phenomenon.

Since the mid-1950s, several nations have flung into Earth orbit (and beyond) numerous satellites carrying numerous sensors for exploring our Universe. Space-based telescopes aboard satellites travel far out into space and radio back huge amounts of data. These new telescopes, or "robots", can "see" in wave­lengths not visible to us humans and extend far beyond what Hubble can see (Hubble: sees visible light plus a slice of infrared EMR).

Different views Observing objects at many, non-visible wavelengths reveals the complexity and beauty of Nature. (Collage by RBKOR of several photos posted by NASA)

With advances in sensors, space-based tele­scopes see images in very short wave­lengths, which have opened whole new avenues of exploration. Where will these new paths of adventure lead or what worth do they have for humanity and for civilization is not yet known. A dearth of human curiosity and imagination is our only limitation to the acquisition of intellectual and practical knowledge. Someday, per­haps, farming and mining will become the domain of space-based robot-colonized eco-systems.

The Orbiting Hubble Telescope has been among the most exciting and productive tools in modern astronomy. Hubble's orbit is above nearly all of the Earth's atmosphere, which permits its 2.4-meter (8-feet, 96-inch) main reflector mirror to clearly see objects that are only a hazy smudge of light when viewed from the surface of the Earth.  

To further appreciate the benefits of viewing the sky from above our atmosphere, consider the Hale reflector telescope in California, which was the first large-scale ground-based reflecting telescope (con­struction completed in 1947). Hubble has a main-mirror diameter of 500 centimeters (200 inches) that is twice the diameter of Hubble's main mirror, yet, Hale could not resolve details that were revealed by space-based Hubble; for example, the Andromeda Nebula was in reality the Andromeda Galaxy.

Microscopes: Seeing the Minuscule

From space, let us return to our desks and see what is going on in the world under a microscope, a device that has been around since the early 17th-century when lens-makers were also exper­imenting with glass-lens telescopes.

Microscopes are the tools we use to see things that are too small to see with the naked eye. Whole new worlds begin to emerge at 10 or 20 times mag­nification.

Students view one-celled amoebas and paramecia swimming around in a mere drop of pond water. The complexity ofPollen {pollem textureAt higher magnification, a creative artist may be inspired by the beautiful surface texture of a tiny grain of pollen. (Image in Public Domain; Wikipedia pollen grains, measuring about 60 micrometers, is revealed under the microscope. Millions and billions of other little creatures and other textures become visible under a microscope.

Optical Microscope Underside of leafThe breathing holes (inset) on the underside of a green leaf can be seen with an optical micro­scope at approx­imately 40 times magnification. (Photos:

At 400x magni­fica­tion, we can see objects as small as 0.5 mm (mil­limeters); equaling 500 μm (microns or micro­meters, which equals 1 millionth of a meter), a dimension ap­proaching the limit of optical microscopes.

If we want to see smaller details, we must turn to ultraviolet light and x-rays. At this degree of "smallness", small bacteria, internal structures of living cells, and the complexities of blood cells become visible.

Electron Microscope Electron microscope manufactured by Emcrafts of Korea; web site:; magnification in the range of 20–200,000 times) Electron micro­scopes can get down to the molecular level, having magni­fication up to, perhaps, 300,000 times or more. These microscopes can display the physical shape of molecules and offer a glimpse of an atom. With this level of knowledge of molecules, we can create new therapeutic drugs and new structural materials for everything from teethe to skyscrapers.  

Because of higher magnification available to us nowadays, we can see more and more structure in the seemingly featureless cytoplasm (the fluid inside a living cell). To observe the fine detail within a living cell, e.g. within ribosomes, mitochondria, chlo­roplasts, and DNA, as well as other structures within the cytoplasm, we must use microscopes that see in wavelengths well-beyond visible light. Extreme ultraviolet light and x-rays have very short wavelengths, short enough to see the fine structure within living cells and molecules.

Review of Metric Units with Respect to One Meter


How Do We See Inside of Atoms?

At the very shortest x-ray wavelengths, we begin to observe the relatively large space between the nucleus of an atom and the electrons whirling around the nucleus. Observing the characteristics of an atom or molecule is possible because the wave­length of extreme x-rays is shorter than the distance between an atom's nucleus and its orbiting electrons.

A Note for the curious: For a radar system to see an airplane, the wavelength of a radar's radio beam must be somewhat shorter than the size of the airplane. Long-range air-traffic control operates around 30 centimeters (1 gigahertz); an airplane is a lot larger than a few centimeters. Athough low-freqeuncy radar systems can detect very large objects, they cannot detect smaller objects, such as fighter jets and automobiles. At shorter wavelength, radar systems can detect smaller objects.

The image is a representation of a functional chip cell built-up in layers of different materials. The heavy base is the silicon substrate. (Graphic by David Carron at English Wikipedia)

Modern com­puter chips are formed by shining the light of x-rays on special coatings sprayed onto a silicon base, i.e. substrate. Through a process that is similar to visual-light litho­graphy, tran­sistors, in­ductors, resistors, and capacitors are formed in layers built-up on the substrate. Wires needed to connect all of these functional elements are also formed on the substrate.  

Chip makers have been relentlessly reducing the size of their chips, because small-dimension chips run faster and run cooler than large-dimension chips. The clock speed of the original IBM Personal Computer was 4.77 megahertz; today's average PC runs at a clock speed of 3 gigahertz or higher, the speed of which is on the order of a thousand times faster. What is no less important is that the cost of making these chips has dropped precipitously as the dimensions of the chips have shrunk.

Particle Accelerators

Berkeley Cyclotron Sixty-inch cyclotron at the University of California Lawrence Radiation Laboratory, August 1939. (Photo in the Public Domain)

If viewing mole­cules is not enough, try firing up a particle ac­celerator (colloqui­ally known as an "atom smasher"). Back in 1932, Ernest O. Lawrence invented a new kind of machine that he called the Cyclotron. A Cyclotron is an early type of particle accelerator that was constructed to study the behavior of atomic particles, particularly protons and neutrons, which in the 1930s were thought to be the smallest parts of an atom. The Cyclotron led to the discovery that protons and neutrons were composed of even smaller particles and were not the primary building blocks of Nature.

Protons and neutrons have structure and can be split into smaller particles, i.e. particles with strange names, such as "quarks", muons [myoo-ahns], neutrinos, and most recently, the Higgs boson, or "god particle". At this level of "smallness", we are getting down to the fundamentals of existence.

Although protons and neutrons are very, very small, studying protons and neutrons requires huge, massive, expensive machines to detect, visualize, and explore the innards of atoms. The largest accelerators are round tunnels that confine protons and neutrons (i.e. particles) within a circular, kilometers-circum­ference, tube-shaped vacuum chamber. Very powerful electromagnets drive the particles around the circle, much like race cars race around a track.

Early accelerators fired one beam of particles into a beryllium or other metallic target and recorded numerous sub-particles that resulted from the collision of the particles with the target. Today, the largest accelerators fire two beams of particles at each other from opposite directions. The collision is like a high-speed, head-on train crash, which produces a shower of smaller particles. The bigger the machine, the smaller the particles detected.

Examining the structure of protons and neutrons at the scale of γ-ray (i.e. "gamma ray") wavelengths very likely will lead us to nearly limitless, sources of energy and fulfill the alchemists' dream of converting base metals into gold. Modern accelerators do change, or transmute, one element to another element of the Periodic Table by colliding different elements. High-energy collisions create a shower of new particles as well as transmuted elements. Unfortunately, these pro­cesses require enormous amounts of electrical energy; so practical "alchemy" machines are not available, YET!

The immediate goal for all of this is to have cheap, plentiful, safe energy. If the quantum physicists persist in their highly esoteric explorations, the dreams of unlimited, near-zero energy cost, inter-galactic travel, quantum computing across galaxies, and stuff that we currently know nothing of, may become one reality among many realities. Let us dream.

Side Note: One may ask, what is the difference between an astronomer and an astrophysicist?  An astronomer observes, while an astrophysicist explains what astronomers have observed. Throughout the millennia, astronomers observed and studied the heavens, but no one had answers to many standing issues, such as:  Is the Earth flat or spherical?  Is the Earth the center of the Universe or is our Sun just a medium-sized, quite ordinary, middle-aged star in a vast sea of innumerable other stars?  Although we have resolved these issues in the last few hundred years, we still have many more mysteries to explain, as well as discovering numerous new mysteries on which to study, ponder, and speculate. The only certainty for now is that knowledge will continue to increase exponentially.  RB


Math Review for the Rusty

10 × 10      =   100
10 × 10 × 10 = 1,000

 A simpler way to write these numbers is called "scientific notation":
10 × 10     = 102
10 × 10 × 10  =  103

 Count the zeros:
102  is represented by two  zeros; we say "ten squared": the area of a square is side 1 × side 2, or ten squared.

103  is represented by three  zeros ; we say "ten cubed": the area of a cube is side 1 × side 2 × side 3, or ten cubed.

10nth  represents any number.

 For numbers less than one, the exponent changes to a negative number: 10−2 = 0.01 and 10−3 = 0.001