Will We Ever Have An Accurate Measurement Of The Universe’s Size?

It’s a small world, or at least we thought it was. Ever since the first accounts of civilization, people have already had a fondness for traveling. Before the discovery of gas-powered automobiles, they’d ride horses. If there weren’t any horses, they’d walk. As long as it lets them go from one point to another, they’d do it.

Thanks to that, we now know many things about this world we live in. Just about anything we see gracing the lands, the seas, and the skies is already part of public knowledge. As vast as that information is, however, there’s still plenty to learn about the world. After all, there are still subjects we haven’t had a full grasp of yet. This, of course, includes the universe. Despite discovering more and more new planets and stars through the years, a few questions remain apparent for many of the world’s researchers: how big is this universe, is it measurable, and will it ever stop expanding?

The Hubble Constant

In the world of science, numbers reign supreme. To further understand things, it’s a must to measure the various aspects of an object, such as its speed and size, among many things. Of course, the universe is no exception to this.

The universe is undoubtedly massive, but by how much, exactly? Well, through the years, researchers have been finding ways to measure it in all its glory. To do this, they would need a reference or a basis. Regarding the universe, that reference is the Hubble Constant, a measurement of how fast it expands. To some degree, it proved to be quite effective. First used by astronomer Edwin Hubble in 1929, the Hubble Constant was initially said to be 500km per second per megaparsec. Decades later, however, revisions were made that reduced its value to between 67 and 74km/s/Mpc. Turns out, the Hubble Constant isn’t as constant as we thought. Nonetheless, there’s no need to panic. A discrepancy such as this isn’t enough to stop researchers.

Cepheid Variables

The Hubble Constant’s value continues to change due to researchers measuring different sources. Thankfully, there is finally a more definitive way of measuring it.

Cepheid variables are stars that have an alternating pattern of dimming and shining. The brighter they are, the longer these intervals become. Discovered by astronomer Henrietta Leavitt, a Cepheid variable’s brightness could then be attained by referring to the time it takes to dim and shine again. Plus, knowing that a star’s light gets dimmer the farther it is from Earth, it’s now fairly easy to measure how far these Cepheid variables are from us. Putting two and two together, this also means that Cepheid variables take credit for being reliable sources to get Hubble Constant’s value. Thanks to that, its measurement is no longer as varied as before, with more current values ranging between 72 and 74km/s/Mpc.

The Plot Thickens

While finding a more stable value of the Hubble Constant is an achievement in its own right, there’s still much to look out for. After all, the universe isn’t like a simple on-and-off switch. It’s like a car that requires numerous things to work for it to be fully functional, and the researchers are the mechanics studying its many parts. Plus, like mechanics, they also come equipped with many useful tools.

Through the years, researchers spend portions of their investment money acquiring state-of-the-art equipment designed to aid their studies. A few notable examples would be ESA’s Gaia, a space observatory tasked with locating billions of the universe’s stars, and the soon-to-be-deployed James Webb Space Telescope. Perhaps soon, these pieces of equipment will widen our horizons. Because right now, only 46 billion light-years of the universe is visible. How much of that occupies the universe, and how much is left to be discovered, you ask? Only time will tell, and of course, plenty of undying determination. Still, 46 billion light-years? That’s a lot of ground – or space, rather – to cover.