What Did Feynman Say About How Science Works

but must be very far away as far as any of the distant galaxies seen. We now

This problem wasn't solved until the 1920s, when Edwin Hubble devised the first method of extragalactic distance measurement. His technique relied on stars known as Cepheid variables, whose luminosities can be easily determined by measuring their rates of pulsation. Comparing this luminosity with the stars' observed brightness allowed Hubble to estimate the distance to Cepheid stars in such galaxies, affirming their extragalactic location.

It is easy to flip to the index of an astronomy textbook to discover that, say, the Sun lies 150 million kilometers away from Earth.  It is far more difficult (if not impossible), however, to picture this distance in the human mind.  In this exercise, we will learn to access the often unpalatable distances encountered in astronomy by simply scaling the huge distances to more recognizable, pedestrian numbers.  So long as every distance within the system of interest is scaled by the same factor, we retain the meaningful information about relative distances between objects.

We can determine an object’s temperature from its thermal (or “blackbody”) spectrum by finding the wavelength at which it emits the most electromagnetic radiation.

Out of the four options, light-years measure the greatest distance. The distance in the other units would be too large. It is easier to read measurements when using a unit that can scale a larger area.

It is easy to flip to the index of an astronomy textbook to discover that, say, the Sun lies 150 million kilometers away from Earth. It is far more difficult (if not impossible), however, to picture this distance in our mind. In this exercise, we will learn to access the often unpalatable distances encountered in astronomy by simply scaling the huge distances to more recognizable, familiar numbers. So long as every distance within the system of interest is scaled by the same

Also, The scale that you are looking at has to perfect. It states in article five, “too big,” and “too small.” For our universe, looking at the universe by minute would take years, but by looking at it from too far, we will not be able to see the thresholds in detail. The scale in which you are using has to be just right to fit the item you are looking at, but still looking at the universe farther away than we would with an apple. We cannot look at an apple from far away, or it would look like a red dot, we would have to look at it from close up to identify it and look at its

In 1820 another French man named James Fourier took the next step in estimating the Earth’s age. He accounted for the fact that the Earth is still hot in its core and using mathematical techniques that he developed and we still use today for time-varying phenomena, came up with a number too staggering foe him to write down. He did however leave us his equations and it is easy to plug in the same numbers and get the answer that he could not say, which comes out to be 100 million years. (Gribbin, 16)

A parallax is used to measure a star’s distance. During every 6 months’ astronomers look at a star and record it they then measure the distance it moved to find the actual distance from the sun.

Astronomers use Cepheid stars to measure distance. First, the period of a distant Cepheid is measured. The period is the length of time between brightness peaks. Next, they measure the peak luminosity of the star itself; this gives them the apparent brightness. Then, assuming that all Cepheids of the same period have the same absolute brightness, the distance is computed

Since velocity is a distance unit by a time unit, unit analysis yields that the inverse of the Hubble Constant is an estimation for the time the universe has been expanding, and if one assumes the universe expands linearly for its life, an estimate of the age of the universe, known as the Hubble Time [3]:

By looking at the different wavelengths or the spectrum of light from a celestial object, you can tell many of its properties and features. To do this, the Hubble Telescope is equipped with various scientific instruments. Each instrument used

Edwin Hubble was an American astronomer who revolutionized cosmology and was regarded as one of the most significant observers in the field. While working at Mount Wilson, Hubble discovered that there were more existing galaxies besides the Milky Way Galaxy. Hubble took many photos through the observatory's telescope, and it allowed him to calculate the distance of other galaxies by comparing the varying degrees of luminosity in the stars themselves. Although there was no evidence suggesting the size of the other galaxies that Hubble discovered, he was ultimately able to compute that the Andromeda Nebula was about one million light years away from us. Later in his career Hubble began to explore the way galaxies shifted in space relative to

The universe is approximately 13.77 billion years old (1). There are two methods which researchers use to determine the age of the universe: observing the oldest stars; and using the Hubble’s constant (1). Observing the star does not mean going outside and looking up in the sky. Using a telescope, researchers can look beyond the human eyes to see a more desirable view of reality in space. Thus, researchers can gather information and determine where the global cluster of stars is located in the universe. Why does it have to be in a cluster? Stars that stay closer to each other indicate that they were formed at the same time (1). The star’s brightness and mass help determine its age (1). A star burns hydrogen as fuel to preserve its brightness;

In Star Wars terms, the key measurement of this study can roughly be likened to measuring the distance between the surface of the Death Star, where multiple rays of light shoot out, and the point where they converge into a single bright beam.