from the world's big
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."
Sallie Krawcheck and Bob Kulhan will be talking money, jobs, and how the pandemic will disproportionally affect women's finances.
Got $55 million lying around? If so, you might be able to score a spot aboard the International Space Station starting 2024.
- NASA awarded a contract to startup Axiom Space to attach a "habitable commercial module" to the International Space Station.
- The project will also include a research and manufacturing module.
- The move is a major step in NASA's years-long push to privatize.
Image: Axiom Space<p>But first, space-tourist-hopefuls would have to pass through physical and medical exams, and 15 weeks of expert training. After that, the trip sounds pretty comfy:</p><p>"There will be wifi," Suffredini <a href="https://www.nytimes.com/2018/06/09/style/axiom-space-travel.html" target="_blank">told the New York Times</a> last year. "Everybody will be online. They can make phone calls, sleep, look out the window. [...] The few folks that have gone to orbit as tourists, it wasn't really a luxurious experience, it was kind of like camping. [...] Pretty soon we're going to be flying a butler with every crew."</p>
A render of the ISS tourist experience.
Image: Axiom Space<p>In a blog post, NASA wrote:</p><p>"Developing commercial destinations in low-Earth orbit is one of <a href="https://www.nasa.gov/press-release/nasa-opens-international-space-station-to-new-commercial-opportunities-private" target="_blank">five elements</a> of NASA's plan to open the International Space Station to new commercial and marketing opportunities. The other elements of the five-point plan include efforts to make station and crew resources available for commercial use through a new commercial use and pricing policy; enable private astronaut missions to the station; seek out and pursue opportunities to stimulate long-term, sustainable demand for these services; and quantify NASA's long-term demand for activities in low-Earth orbit."</p>
NASA's push to privatize the ISS<p>When a Russian rocket launched the first module of the ISS into space in 1998, NASA expected the space station to operate for about 15 years. But the agency has extended the life of the ISS twice, with funding currently set to expire in 2024. NASA spends between $3 and $4 billion per year operating and shuttling astronauts to and from the station. That's a decent chunk of the agency's $22.6 annual budget. What's more, the "major structural elements" of the ISS are certified only through 2028.</p><p>Meanwhile, NASA has been eyeing other projects, namely: putting humans back on the moon in 2024 and establishing a lunar presence. So, to save and redirect money, the agency has been starting to hand over the aging space station to the private sector, which could use it for commercial research and space tourism.</p><p>But some have questioned the move to privatize the ISS, including NASA's own inspector general, Paul K. Martin.</p><p>"An obvious alternative to privatization is to extend current ISS operations," Martin wrote in a <a href="https://oig.nasa.gov/docs/CT-18-001.pdf" target="_blank">2018 report</a>. "An extension to 2028 or beyond would enable NASA to continue critical on-orbit research into human health risks and to demonstrate the technologies that will be required for future missions to the Moon or Mars."</p>
Image: Axiom Space<p>Martin noted that "research into 2 other human health risks and 17 additional technology gaps is not scheduled to be completed until sometime in 2024," meaning that any slip-ups in the process would mean such research might go uncompleted. He also wrote that it's "questionable" whether the private sector could turn a profit on the ISS without "significant" government funding. The Institute for Defense Analyses, a federally funded research and development center, <a href="https://docs.house.gov/meetings/SY/SY00/20180517/108302/HHRG-115-SY00-Wstate-LalB-20180517.pdf" target="_blank">also found</a> that it "is unlikely that a commercially owned and operated space station will be economically viable by 2025."</p><p>The implication is that, if the ISS is handed over to the private sector, taxpayers could end up indirectly supporting space tourism for the ultra-rich. Whether that's worth any of the research benefits that might come from the ISS post-2024 is anybody's guess.</p><p>As the ISS enters its final years, China <a href="http://www.xinhuanet.com/english/2019-10/17/c_138479514.htm" target="_blank">plans</a> to complete construction of a manned space station in 2022.</p>
The coronavirus pandemic has brought out the perception of selfishness among many.
- Selfish behavior has been analyzed by philosophers and psychologists for centuries.
- New research shows people may be wired for altruistic behavior and get more benefits from it.
- Crisis times tend to increase self-centered acts.
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