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The universe is dying, new study confirms
Star production peaked three billion years after the Big Bang.
- Scientists track gamma rays across the universe's extragalactic background to calculate all of the starlight ever produced.
- For 10.8 billion years, star production has been decelerating.
- The research team measured nine years worth of data from the universe's 739 known blazars.
The good news is that scientists believe they've figured out how much starlight the universe has ever produced since the Big Bang. Exciting. The bad news? Well, apparently star production peaked a long, long time ago, and ever since, the universe has been in the process of dying. Only seven new stars are born a year these days. You can keep buying green bananas, though; there's time: We still have many billions of years before the stars that already exist go dark and cold.
In Science, the Fermi-LAT Collaboration published, on November 30, a new inventory and history of the universe's light. So, how much light has the universe produced? 4 × 10⁸⁴ photons. To spell that out, that's 4,000,000,000,000,000,000,000,000,000,000,000,000
The lead study author of the study, astrophysicist Marco Ajello, said his team was able to measure the entire amount of starlight ever emitted using the Fermi telescope.
"This has never been done before," he told Clemson University's the Newsstand. "Most of this light is emitted by stars that live in galaxies. Every single star that has existed has contributed to this emission, and we can use it to learn all the details about star formation and evolution and galaxy evolution."
The Fermi team has been measuring nine years worth of data from the universe's 739 known blazars.
This map of the entire sky shows the location of 739 blazars used in the Fermi Gamma-ray Space Telescope's measurement. Brighter areas have stronger gamma rays.
Image: NASA/DOE/Fermi LAT Collaboration
What the blazar is a blazar?
As galaxies spin around a supermassive black hole at their center, charged particles circling the event horizon develop strong magnetic fields that further excite the particles, causing them to emit radiation at very high energies. Such galaxies produce a great deal of light at their centers, and they're referred to as "active galactic nuclei" (AGN). Some AGNs seem brighter than others from here on Earth. They're not really — they're just the ones pointed straight at us.
Jets of material shot out of such AGNs are called "blazars." The quasar sound-alike name gets its "Bl" from "BL Lacertae," after the constellation in which the first recorded one, back in 1929, originated. Blazars travel at near light speed, and within them are gamma-ray photons the Fermi Gamma-ray Space Telescope is designed to detect.
Artistic rendering of a blazar accelerating protons that produce pions, which produce neutrinos and gamma rays. Image source: IceCube/NASA
Encounters with the EBL
As they travel across space, blazar gamma-ray photons collide with the universe's extragalactic background (EBL), the background radiation produced by star formation. Says Ajello, "Gamma-ray photons traveling through a fog of starlight have a large probability of being absorbed. By measuring how many photons have been absorbed, we were able to measure how thick the fog was, and also measure, as a function of time, how much light there was in the entire range of wavelengths." He adds, "It's like following the rainbow till the end and finding the treasure. That's what we found."
In terms of the blazars, NASA columnist Ethan Seigel writes, "The closest one comes to us from just 200 million years ago; the most distant has its light arriving after a journey of 11.6 billion years: from when the Universe was just 2.2 billion years old."
Artist's conception of a blazar. Image source: JPL
The timeline behind and ahead
The study's Vaidehi Paliya says, "By using blazars at different distances from us, we measured the total starlight at different time periods. We measured the total starlight of each epoch — 1 billion years ago, 2 billion years ago, 6 billion years ago, etc — all the way back to when stars were first formed."
The notion that the universe is "dying" is due to the fact that star production, which is decreasing, is a grand recycler of energy, matter, and elements that "nourish" the universe. Our survival relies, quite literally, on starlight and its generation. As Dieter Hartmann, another author of the study, says: "Without the evolution of stars, we wouldn't have the fundamental elements necessary for the existence of life."
Join multiple Tony and Emmy Award-winning actress Judith Light live on Big Think at 2 pm ET on Monday.
Your favorite color can be linked to various personality traits, motivation, and productivity levels in your life.
- Color psychology has been used in marketing and branding for years, but research in the last decade has taken color psychology and applied it to human personality traits.
- Colors aren't merely associated with various feelings but can actually shape our perceptions and personalities.
- Various studies across multiple years have given us insight into what each color represents in regards to our personality, work ethic, and motivation levels.
What is color psychology?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjkzNDU4MC9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTY0Mzc2Mzk4NX0.KqHFgzhzl-dKmUvgDZsYGEDgDPVU40mA2mV1GLb1a68/img.png?width=1500&coordinates=0%2C0%2C0%2C0&height=1314" id="109d8" class="rm-shortcode" data-rm-shortcode-id="42ec0b499017c39ed1e3df32308370c2" data-rm-shortcode-name="rebelmouse-image" alt="The Logo Company color marketing infographic" />
Colors have been used strategically in branding for years.
Image by The Logo Company<p>Many people are unaware of the impact colors have on our thoughts, emotions, and behaviors in everyday life.</p><p>It's extremely likely that you have purchased something in a store or chosen one product over another due to what brands call color marketing: targeting brands, colors, and adverts based on colors that will influence you to buy. </p><p>You can see in the infographic above that companies that want to be associated with dependability (Dell, HP, IBM) use the color blue. Companies that want to be known for being exciting and fun (Fanta, Amazon, Nickelodeon) use a splash or orange. </p><p>Color psychology is being used around us every single day and not only in what brands we buy, but also in how we react to our environment. Extending color psychology into the realm of personalities is about proving that colors aren't just about what looks the best, but about what meaning we subconsciously attach to those colors, and how to use that to benefit our lives.</p>
What your favorite color says about your personality<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjkzNTc2Ny9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0NTc2MTU1NH0.iLH4yQoMFZMDW1YJo1YRMR8jOZDfDd3PFdu_IynkBcM/img.jpg?width=980" id="6e5e9" class="rm-shortcode" data-rm-shortcode-id="5b38c0f7793933f9ab35a61a2f7bb14a" data-rm-shortcode-name="rebelmouse-image" alt="child holding crayons" />
A new study looks at what would happen to human language on a long journey to other star systems.
- A new study proposes that language could change dramatically on long space voyages.
- Spacefaring people might lose the ability to understand the people of Earth.
- This scenario is of particular concern for potential "generation ships".
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