Everyone knows that the universe is massive. It is home to millions of galaxies, an incredulous amount of stars, and too many other celestial objects to even try to count. The universe reaches far beyond our reach, making it difficult to determine its size.
Many astronomers agree the universe is right around 46 billion light-years in radius. This measurement would mean, in total, it is around 93 billion light-years in size. However, this is an estimation based on what we can see.
So, how immense is the universe? Let’s examine what many professionals have done to answer this question and discuss other interesting facts that help support their claims.
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Finding the Size of the Universe
Since everything we know is encased inside the universe, it is safe to say that it is pretty big. And due to its enormous size, it was very complicated for astronomers to determine just how big it actually was. But they did. Well, sort of.
It can be hard to know how big the universe is since it is rapidly increasing each day.
Putting that aside, astronomers have been able to put an “at best’ estimate on its actual size based solely on how far they can see from here on Earth. Well, how did they do this?
The tools utilized to determine the universe’s massive size come from many generations of astronomers, scientists, mathematicians, and various other professionals around the world.
Most of the answers come from knowledge regarding trigonometry, the Pythagorean theorem, geometrics, etc. (And we thought math class was a waste of time.)
Creating a Distance Ladder Starting With the Parallax Method
In short, experts could use math skills and objects in space to determine how big galaxies are and the size of the universe, give or take a few light years.
It is easy to measure large objects at far distances once we have a shorter, closer measurement to compare them to. For example, you want to know the height of a fence, but you don’t have a measuring tape. Well, you know that you stand six feet tall, and the fence comes right in line with your mid-section; you can deduce the fence is around three feet tall.
Similarly, if we were to measure an object closer to Earth in space, we can determine how much farther out other objects are that have more distance between them and the Earth.
Let’s take a relatively close star, for example. If astronomers were to measure the distance of one particular star in January, they could use that measurement in June to determine the distance of another star in a similar location.
Using the angle of light in the two locations on opposite sides of one another can give us a good idea of just how big the universe really is.
The Problem and Solution
While the above method is an excellent tool, it doesn’t work with every star. This takes a specific star called Cepheids. These stars will pulsate, giving off a bright light while pulsating for long periods and dimming during short periods of pulsation.
Using the above parallax method, you can compare the pulsation length between a nearby Cepheid and those much further. With this technique, astronomers can move further up the ladder system to supernovas using this technique.
Because the Cepheids only reach as far as eighty million light-years away, it isn’t sufficient enough to assist in measuring beyond that distance. However, supernovas (the enormous explosions that come from a white dwarf star (a dead star in a two-star system) feed off of the live star until it bursts.
This explosion is so bright it helps us to measure the distance to the galaxies that are extremely far away.
We’re Almost There
Now that we can calculate the cosmic distance to these far-away supernovas, we can move even further into the universe using the Hubble Constant. This method proved that the light would look red when things move farther away, and things moving closer are blue.
The light change comes from the stretching or retracting of electromagnetic spectrum energy. Because the light of galaxies extremely far away appears to have a red light, it is safe to say they continue moving further out.
This method made it possible for Hubble (the genius who figured this all out) to use it with the constant expansion of the universe and everything in it to estimate its size.
But Wait, There Is One More Piece to This Puzzle
Cosmic microwave backgrounds are radiation leftovers from the aftermath following the Big Bang. Using the cosmic wave backgrounds, astronomers know where the early universe began, giving them a good idea of how large it is.
The Moment You Have All Been Waiting For
Using the ladder method, astronomers have estimated that the universe is roughly 94 billion light years, with the most distant objects being around 47 billion light years away from planet Earth, according to NASA in 2006.
Let’s put it into terms that are easier for us to understand. One single light year equals six trillion miles. Now, multiply that by 94 billion, and that is a LOT of miles.
Although the route of getting to that conclusion was long, it was essential to take things step by step to give you an idea of how difficult it is to determine an exact number.
The Universe Is Still Expanding
Chances are good that number is even higher today as the universe is constantly expanding, and the size will vary depending on who you ask. So, it is best just to say that the size of the universe is MASSIVE.
Since it’s believed the Big Bang happened roughly 13.7 billion years ago, it is nearly impossible to get the exact size of the universe. And that is if there even is one. Many people believe the universe is infinite and never-ending, and they may be right.
Dark Matter and Energy
Dark matter and dark energy are invisible matter that comprises 95% of the universe. This matter has gravity, but you cannot see it, and we cannot be sure how far out it stretches. Due to the mysterious circumstances surrounding dark matter, there is no way any astronomer can be sure just how much larger the universe may be.
The Size of Objects Inside Our Universe
We might not have an exact answer for you regarding the size of the universe, but we can tell you how big other celestial objects are.
- The Sun: Our solar system’s largest object is around 865,000 miles in diameter.
- The Moon: The moon is much smaller than the sun, with a circumference of 6,783.5 miles.
- The Earth: The Earth is the largest inner planet, measuring 7,900 miles in diameter.
- The Milky Way Galaxy: The spiral galaxy is around 100,000 light-years across.
- The Northern Star: Brighter than the sun, the Northern star is still visible because it is 70 million kms in size.
- Pluto: Pluto is a dwarf planet, about 1,472.6 miles in diameter.
- Venus: 7,520.8 miles in diameter and has 81.5% of the mass of Earth.
- Mercury: Mercury is a small planet with a 3,000-mile diameter.
- Saturn: Saturn is over nine times the size of Earth, with a 75,000-mile diameter.
- Neptune: Neptune is extremely large compared to the other planets, with a diameter of 2.8 billion miles.
- Mars: Mars is the second smallest planet in the solar system, coming in at 2,106 miles in diameter.
Can you even begin to imagine just how big the entire universe might be? Think about how far apart each of the objects listed above is and how big they are. In our solar system alone, the room needed to create enough space for all this celestial stuff is incomprehensible.
The Milky Way is the band of stars and other space debris that swirls in correspondence to the plane of our galaxy. This is just one galaxy out of hundreds of billions we can see in the universe. (Mind. Blown.)
When you consider all of the facts regarding what makes up the universe, it is easy to understand how any astronomer (or Carl Sagan or Albert Einstein, for that matter) can have a tough time nailing down exactly how big it could be.
The Universe Is Just Too Big to Measure
A quick and easy answer to how big the universe is is that we simply don’t know. No ruler, measuring tape, or other tools is big enough for this task. Not even the Hubble space telescope or the James Webb space telescope.
We can only generate rough estimates based on scientific calculations, impressive math skills, and comparing measurable objects to unmeasurable ones. That doesn’t mean astronomers aren’t getting closer to figuring it all out.
