Linde’s chaotic inflation theory models of the early universe .
In 1923, Hubble proved that the Andromeda Galaxy was not a nebula within our Milky Way, but rather an independent galaxy 2.2 million light years distant. He showed that our Milky Way galaxy was no longer the center of the universe which gave us some sense of the true scale of our cosmic neighborhood. He later showed that all of the galaxies in the universe are moving away from each other. This means that the universe is expanding. In connection with that he also developed something called Hubble’s Law, which states that v=HoD. In other words, the speed with which a galaxy is moving away from us equals its distance from us times the Hubble constant. Although the value of Hubble’s constant was calculated by Sandage and Tamman to be approximately 50 Kilometers per second per megaparsec, there are some scientists who feel that this value is far too low.
In the mid-1970s, Vera Rubin began to study the rotation speeds of galaxies in an effort to understand why galaxies have different shapes (spirals, spheroids, irregular, etc). Since galaxies are vast collections of stars, nebulae, and other material, Rubin thought a good starting point would be to study the orbital patterns of stars in various portions of the disk at a range of distances from the center. After observing about 20 (and then 40, 100 and so on), Rubin noticed that the line was straight: meaning that the stars near the center of the disk, the ones half to the edge, and the ones at the edge of the galactic disk were all traveling at the same speed. [The result that was expected was something more familiar, like our own solar system, where those masses close to the center - like the planet Mercury - orbit quite fast (88 days), while by the time you get out to a planet like Pluto it takes 248 years for it to circle the Sun.]
One big challenge in astronomy is to measure cosmic distances. How do we know anything about objects 10 thousand light years away (10+20 meters)? This is emphatically a problem of scale. Though we can use triangulation by making two observations of the same object 6 months apart (in other words, when the Earth is at the two extremes of its orbit), this is only effective for measuring relatively short distances. For objects many thousands or millions of light-years away we cannot do anything active.
Standard candles are one of the critical ways we have found to help us measure cosmic distances. The principle is quite simple: if you could find an object whose luminosity (brightness) you knew absolutely just by looking at it, then, by comparing the apparent luminosity with the absolute luminosity, you could figure how far away it is. In 1912, Harvard astronomer Henrietta Leavitt discovered an extraordinarily consistent pattern: that certain stars with variable brightness followed a very strict relationship between their absolute luminosity and the period of their variable brightness - they’re known as Cepheids after the constellation in which they were first discovered.
The telescope has contributed more to our understanding of the heavens than any other single physical tool. There are two kinds of optical telescopes: refractors and reflectors.
10+16 meters is an important landmark in space - 1 light-year, the distance a beam of light can travel in a year.
Though we are beyond the 8 (or so) planets of the traditional solar system, there are objects here that are still within the thrall of the Sun’s gravitational pull. Although it is weaker here - no question (gravity falls off exponentially) - the longer interval comets and other objects are still centered around the Sun.
The three arcs that you see represent the paths traveled by three planets; the green arc represents the six-week-long path traveled by the Earth each September and October. The other two paths are of Earth’s closest neighbors: Mars and Venus.
In terms of space, 10+08 is 100,000 kilometers or the distance that the earth travels in one hour. The Earth, the third planet from the Sun, and the fifth largest planet, orbits the Sun at an average distance of 93 million miles.
10+06 is the scale of nations and continents.
This is the scale of the town or village - or the neighborhood of today’s modern city. It is also the scale of the everyday heroics of engineering.
This is the scale of big buildings - not necessarily the biggest, but the substantial structures that make up the modern city.
If the human scale was, in a sense, about the individual, then at this scale we begin to reach out to our most intimate community - our family. This is the scale of the home, of language, of conversation.
This is the human scale - roughly the size of a human being.
This is the scale of the hand. For human beings, there has always been a special connection between the hand and the mind. Our brain is specially wired to learn using this connection. Perhaps this accounts for the primal fascination of the well-crafted object.
This is a scale that we understand. We manipulate things at this scale, interrogate them with our touch, and then, from this touchstone of scale, we often try to apply our learning and metaphors to other scales.
We are at the scale of biomechanics - the scale at which fine surgeons operate. The scale where cells communicate with each other, where the brain’s neurons begin to conglomerate into regions, where cells become vessels.
10-05 (100 microns) is also the scale of the jewel-like organisms called diatoms, once avidly collected during Victorian England’s microscope craze. These improbable organisms have a body of glass and, although related to algae, many have the capability of self-locomotion.
And, of course, a beam of light of this wavelength would be considered infrared or ultraviolet.
100 nanometers = 1000 angstroms
10 nanometers = 100 angstroms
This is the scale of strands of DNA, of viruses and prions.
1 nanometer = 10 angstroms
This is the scale of simple molecules and the building blocks of DNA. We are now moving from the realms of pure physics and chemistry into the simplest structures of biology. It is no longer enough to know which atom is which, it is how and with which other ones they connect that becomes important at this scale. Part of the magic though, is that all the forces, subatomic and atomic that were in play before are included in the connections that make up life. Chemistry doesn’t stop being chemistry just because it is biochemistry, it just has a different kind of richness.
100 picometers = 1 angstrom
We are at the scale of the inner electron shell. This shell is not an actual shell or even an actual orbit of a planet, it is a kind of zone of the probability of finding these electrons of the inner shell.
The journey of understanding electricity, grasping the unity of magnetism and electricity and the discovery of the electron, were key stepping stones in understanding this scale. Each discovery built on the last.
A final reminder, all the images of the atom and smaller are different than the images of larger scales, such as the chair seen to our right. While the chair looks pretty much like that picture, this Powers of Ten image is, in a sense, a model of what things are like at this scale. We can not see anything at this scale, in the sense we usually mean it. This is because when we see, we see light reflecting off an object. Well, this electron shell is far tinier than the wavelengths of visible light, so there is no information to be reflected and taken in by our retinas. So we must model it instead. It is why there are no photographs of atoms in the way we would think of a typical photo.
As the vast emptiness of the interior of the atom dominates this power of ten in Space, this makes it an appropriate order of magnitude to consider this scale in Time. To get a feeling for how short this is, if you were racing to the Sun and were fast enough to get there in one second, after 10-13 seconds you would have traveled only half an inch.
But although 10-13 seconds may seem impossibly small, as we have already seen, atomic clocks are more precise than this. This is the scale of certain lasers, used in surgery and used to manipulate time itself. A femtosecond laser (10-13 seconds is 100 femtoseconds) refers to how often a pulse of light is emitted in the laser. And many meaningful aspects of this scale in time are best manifested at this scale in space as well.
This is the scale of the nucleus of the atom. The number of protons in the nucleus determines what element a given atom is. For example, the carbon atom has 6 protons - and 6 neutrons (the number of neutrons in an atoms nucleus can vary, but change the number of protons and you change what element it is). The image above shows a representation of the nucleus of a carbon atom.
