For almost a century, astronomers have understood that the Universe is in a state of expansion. Since the 1990s, they have come to understand that as of four billion years ago, the rate of expansion has been speeding up. As this progresses, and the galaxy clusters and filaments of the Universe move farther apart, scientists theorize that the mean temperature of the Universe will gradually decline.
But according to new research led by the Center for Cosmology and AstroParticle Physics (CCAPP) at Ohio State University, it appears that the Universe is actually getting hotter as time goes on. After probing the thermal history of the Universe over the last 10 billion years, the team concluded that the mean temperature of cosmic gas has increased more than 10 times and reached about 2.2 million K (~2.2 °C; 4 million °F) today.
For the sake of their study, the the team examined thermal data on the Large-Scale Structure (LSS) of the universe. This refers to patterns of galaxies and matter on the largest of cosmic scales, which is the result of the gravitational collapse of dark matter and gas. As Dr. Chiang explained in an Ohio State News release:
“Our new measurement provides a direct confirmation of the seminal work by Jim Peebles — the 2019 Nobel Laureate in Physics — who laid out the theory of how the large-scale structure forms in the universe. As the universe evolves, gravity pulls dark matter and gas in space together into galaxies and clusters of galaxies. The drag is violent — so violent that more and more gas is shocked and heated up.”
To measure thermal changes over the past 10 billion years, Chiang and his colleagues combined data from by the ESA’s Planck Infrared Astronomical Satellite and the Sloan Digital Sky Survey (SDSS). Whereas Planck was the first European mission to measure the temperature of the Cosmic Microwave Background (CMB), SDSS is a a massive multi-spectral survey that has created the most detailed 3D maps of the Universe.
From these data sets, the team cross-correlated eight of Planck‘s sky intensity maps with two million spectroscopic redshift references from the SDSS. Combing redshift measurements (which are routinely used to determine how fast are objects are moving away from us) and temperature estimates based on light, the team compared the temperature of more distant gas clouds (farther back in time) with those closer to Earth.
From this, the research team was able to confirm that the mean temperature of gases in the early Universe (ca. 4 billion after the Big Bang) was lower than it is now. This is apparently due to the gravitational collapse of the cosmic structure over time, a trend which will continue and become more intense as the expansion of the Universe continues to accelerate.
As Chiang summarized, the Universe is warming because of the natural process of galaxy and structure formation, and is unrelated to temperature changes here on Earth:
“As the universe evolves, gravity pulls dark matter and gas in space together into galaxies and clusters of galaxies. The drag is violent — so violent that more and more gas is shocked and heated up… These phenomena are happening on very different scales. They are not at all connected.”
In the past, many astronomers have argued that the cosmos would continue to cool as it expanded, something that would inevitably result in the the “Big Chill” (or “Big Freeze”). In contrast, Chiang and his associates showed that scientists can clock the evolution of cosmic structure formation by “checking the temperature” of the Universe.
These findings could also have implications for theories that accept “cosmic cooling” as a foregone conclusion. On the one hand, it has been suggested that a possible resolution to the Fermi Paradox is that extraterrestrial intelligences (ETIs) are dormant and waiting for the Universe to improve (the Aestivation Hypothesis).
Based in part on the thermodynamics of computing (the Landauer’s Principle), the argument states that as the Universe cools, advanced species would be able to get far more out of their megastructures. Also, if the cosmos is going to get hotter over time, does that mean that the emergence of life will become less likely over time due to increased cosmic radiation?
Assuming there is no mechanism for maintaining a certain thermal equilibrium, would this mean that the Universe will not end in a “Big Chill,” but a “Big Blaze”? As Robert Frost famously wrote, “Some say the world will end in fire, others say in ice.” Which of these will prove to be correct, and what implications it could have for life in the future, only time will tell…
Great news! It turns out scientists have discovered that we’re 2,000 light-years closer to Sagittarius A* than we thought.
This doesn’t mean we’re currently on a collision course with a black hole. No, it’s simply the result of a more accurate model of the Milky Way based on new data.
From the cosmos to your inbox. Get the latest space stories from CNET every week.
Over the last 15 years, a Japanese radio astronomy project, VERA, has been gathering data. Using a technique called interferometry, VERA gathered data from telescopes across Japan and combined them with data from other existing projects to create what is essentially the most accurate map of the Milky Way yet.
By pinpointing the location and velocity of around 99 specific points in our galaxy, VERA has concluded that the supermassive black hole Sagittarius A, at the center of our galaxy, is actually 25,800 light-years from Earth — almost 2,000 light-years closer than what we previously believed.
In addition, the new model calculates Earth is moving faster than we believed. Older models clocked Earth’s speed at 220 kilometers (136 miles) per second, orbiting around the galaxy’s centre. VERA’s new model has us moving at 227 kilometers (141 miles) per second.
VERA is now hoping to increase the accuracy of its model by increasing the amount of points it’s gathering data from by expanding into EAVN (East Asian VLBI Network) and gathering data from a larger suite of radio telescopes located throughout Japan, Korea and China.
Researchers have effectively confirmed one of the most important theories in star physics. NBC Newsreports that a team at the Italian National Institute for Nuclear Physics has detected neutrinos traced back to star fusion for the first time. The scientists determined that the elusive particles passing through its Borexino detector stemmed from a carbon-nitrogen-oxygen (CNO) fusion process at the heart of the Sun.
This kind of behavior had been predicted in 1938, but hadn’t been verified until now despite scientists detecting neutrinos in 1956. Borexino’s design was crucial to overcoming that hurdle — its “onion-like” construction and ongoing refinements make it both ultra-sensitive and resistant to unwanted cosmic radiation.
It’s a somewhat surprising discovery, too. CNO fusion is much more common in larger, hotter stars. A smaller celestial body like the Sun only produces 1 percent of its energy through that process. This not only confirms that CNO is a driving force behind bigger stars, but the universe at large.
That, in turn, might help explain some dark matter, where neutrinos could play a significant role. Scientist Orebi Gann, who wasn’t involved in these findings, also told NBC that an asymmetry between neutrinos and their relevant antiparticles might explain why there isn’t much known antimatter in the universe. To put it another way, the findings could help answer some of the most basic questions about the cosmos.
All products recommended by Engadget are selected by our editorial team, independent of our parent company. Some of our stories include affiliate links. If you buy something through one of these links, we may earn an affiliate commission.
Privacy & Cookies Policy
Necessary cookies are absolutely essential for the website to function properly. This category only includes cookies that ensures basic functionalities and security features of the website. These cookies do not store any personal information.
Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. It is mandatory to procure user consent prior to running these cookies on your website.