How to Measure the Universe

Measure The Universe Au Astronomical Image

How indeed, do we measure something that many believe to be infinite? Measurement itself is a man made concept, so in some ways the answer might be “any way we like”, but there are a few models for cosmological measurement that have come to be accepted by the scientific community.

Accepted Standards

For a race that once thought it was the centre of the universe, how else would Mankind measure the Universe except in reference to itself? Take, for example, the Astrological Unit, or AU. We measure distance in a few ways in space, including light years, but also in AU. One AU is the distance from the Earth to the Sun, or 150 million kilometres. This is how the astronomers of Earth had to begin the process of measuring that which they were still (and are still) learning about. As is proven by the relatively recent demotion of Pluto from Planet to dwarf planet, these units of measurement and defining terms are subject to change.

Time

We measure time in the Universe the same way we measure it on Earth. When talking about the age of the Universe, for example, it is estimated at 13.7 billion years, and years refers to Earth years.

Distance

As mentioned above, a common cosmological unit of measurement is the AU. Also in use is the Light Year, which is the distance light can travel through unhindered space in one earth year. A light year is roughly equivalent to 63,240 AU, or nearly 9.5 trillion kilometres.

Counting

How many planets are there in a solar system, how many solar systems are in a galaxy, and how many galaxies are there in the universe? We strive to catalog as much of the universe as we can, and so we count. There are, roughly, eight planets in the solar system (thanks to the new definition of planet given by the International Astronomical Union), which revolves around our star, the Sun. There are estimated to be somewhere between 200 and 400 billion stars in the Milky Way, our galaxy, alone. It is believed that there are billions of galaxies in the universe.

Observation

Outside of naming and record keeping, the main way we measure the Universe is through observation. It is the way Mankind measures everything, but observing what things are and how they impact the other things around them. By observing how the stars appeared to wheel in the sky, early astronomers were able to begin calculating the shape of the universe. By building devices to record energy radiating from distant stars current astronomers are able to extrapolate distant planets that would otherwise remain undiscovered. By noting the redshift of distant galaxies Edwin Hubble was able to figure out that they were moving, and from there scientists were able to create theories about how the universe was formed.

Final Thoughts

A key component in good science, and good scientists, is observation. Taking note of the world around us—and the universe around our world—allows us to learn about it and thus better ourselves. We measure the universe in the same manner.