from the world's big
Why the universe's ancient galaxies were extra bright
New research based on observational data from the Spitzer telescope provides clues as to how the universe first emerged from its dark age.
- Researchers using the Spitzer telescope were able to analyze some of the most distant and ancient galaxies in the universe.
- They discovered that these galaxies were far brighter than anticipated, shedding clues into how the universe first emerged from the "dark ages" that lasted until about a billion years after the Big Bang.
- This research serves as a stepping stone for future work to be conducted with the James Webb Space Telescope, scheduled to be launched in early 2021.
One might imagine that history of the universe is a gradual fading out, that the Big Bang was incredibly bright and dense and gradually everything dispersed and dimmed until the small pinpricks of distant stars and galaxies distributed to where we see them in our sky today. This idea, however, isn't entirely accurate. The universe has gone through several dramatic changes. For example, after the Big Bang, the universe was a very dark place until the first stars "turned on" during a period called the Epoch of Reionization. Now, new research published in the Monthly Notices of the Royal Astronomical Society shows that the early galaxies during this period were extraordinarily bright, providing clues to how we came to find stars in our sky.
What was the Epoch of Reionization?
Soon after the Big Bang, there were no stars, galaxies, or really anything you could refer to as an object. Instead, there was a miasma of hydrogen gas. It took a long time for gravity to gather enough gas together to form stars — about 200 million years after the Big Bang — but even once that happened, the universe was still relatively dark.
One would think that once stars had formed, the universe would have emerged from its so-called dark age, but much of the light spectrum was blocked by the omnipresent hydrogen gas that existed in the universe at this time. Forms of light with long wavelengths like radio waves and visible light could pass through this gas unencumbered, but shorter, more energetic forms of light like UV light, X-rays, and gamma waves were blocked. This is because the hydrogen gas was neutral, meaning it carried no electrical charge. High-energy waves of light would strike the neutral hydrogen atoms and be blocked by them, stripping them of their electrons in the process. This is known as ionization.
Ionized hydrogen allows much more light to pass through it. Today, the universe is filled with ionized hydrogen, though it is much less dense than it used to be. But this transition is still something of a mystery. What could have produced all of this ionizing radiation? Lead study author Stephane De Barros called this "one of the biggest open questions in observational cosmology. We know it happened, but what caused it? These new findings could be a big clue."
What did the researchers discover?
This deep-field view of the sky (center) taken by NASA's Hubble and Spitzer space telescopes is dominated by galaxies — including some very faint, very distant ones — circled in red. The bottom right inset shows the light collected from one of those galaxies during a long-duration observation.
NASA / JPL-Caltech / ESA / Spitzer / P. Oesch / S. De Barros
Using the Spitzer telescope, the research team collected data from two regions in the sky for over 400 hours. Because light can only go so fast, looking at very distant objects is the same as looking at those objects in the past: What we see in our telescopes is the result of light that has taken, in some cases, billions of years to reach us. Through Spitzer, the research team was able to observe very distant galaxies from 13 billion years ago, right at the end of the Epoch of Reionization.
Specifically, the team observed 135 galaxies, and they found specific wavelengths of infrared light that are produced when ionizing radiation interacts with hydrogen and oxygen gas, the kind of activity that would be going on during the Epoch of Reionization. Surprisingly, this light was far brighter than expected; these early galaxies were spewing out an astounding amount of ionizing radiation, contributing to the transformation of the universe to how it appears today. This study suggests that these extra-bright galaxies (which outshine current galaxies by far) were the norm during this period.
The fact that Spitzer was capable of observing these distant and ancient galaxies was itself a surprise, considering it's only about 33 inches in diameter. While Spitzer is an admirable instrument, it's important to note that any tool used to look this far back into the past will be subject to a lot of error. The researchers tried to account for the many variables that could affect their analysis, like the impact of nebulae and dust grains.
Waiting for the James Webb Space Telescope
The James Webb Space Telescope is scheduled for launch on March 30th, 2021, and its capabilities will blow Spitzer out of the water. Similar to this work, Webb's job will be to look at some of the most distant and ancient objects in the universe. While Webb will be tuned to observe many of the same wavelengths as Spitzer, it will be about 7.5 times larger. Using research such as this, scientists hope to gain insight into how these super-bright galaxies formed and even how the first galaxies ever came to be.
Andy Samberg and Cristin Milioti get stuck in an infinite wedding time loop.
- Two wedding guests discover they're trapped in an infinite time loop, waking up in Palm Springs over and over and over.
- As the reality of their situation sets in, Nyles and Sarah decide to enjoy the repetitive awakenings.
- The film is perfectly timed for a world sheltering at home during a pandemic.
Richard Feynman once asked a silly question. Two MIT students just answered it.
Here's a fun experiment to try. Go to your pantry and see if you have a box of spaghetti. If you do, take out a noodle. Grab both ends of it and bend it until it breaks in half. How many pieces did it break into? If you got two large pieces and at least one small piece you're not alone.
But science loves a good challenge<p>The mystery remained unsolved until 2005, when French scientists <a href="http://www.lmm.jussieu.fr/~audoly/" target="_blank">Basile Audoly</a> and <a href="http://www.lmm.jussieu.fr/~neukirch/" target="_blank">Sebastien Neukirch </a>won an <a href="https://www.improbable.com/ig/" target="_blank">Ig Nobel Prize</a>, an award given to scientists for real work which is of a less serious nature than the discoveries that win Nobel prizes, for finally determining why this happens. <a href="http://www.lmm.jussieu.fr/spaghetti/audoly_neukirch_fragmentation.pdf" target="_blank">Their paper describing the effect is wonderfully funny to read</a>, as it takes such a banal issue so seriously. </p><p>They demonstrated that when a rod is bent past a certain point, such as when spaghetti is snapped in half by bending it at the ends, a "snapback effect" is created. This causes energy to reverberate from the initial break to other parts of the rod, often leading to a second break elsewhere.</p><p>While this settled the issue of <em>why </em>spaghetti noodles break into three or more pieces, it didn't establish if they always had to break this way. The question of if the snapback could be regulated remained unsettled.</p>
Physicists, being themselves, immediately wanted to try and break pasta into two pieces using this info<p><a href="https://roheiss.wordpress.com/fun/" target="_blank">Ronald Heisser</a> and <a href="https://math.mit.edu/directory/profile.php?pid=1787" target="_blank">Vishal Patil</a>, two graduate students currently at Cornell and MIT respectively, read about Feynman's night of noodle snapping in class and were inspired to try and find what could be done to make sure the pasta always broke in two.</p><p><a href="http://news.mit.edu/2018/mit-mathematicians-solve-age-old-spaghetti-mystery-0813" target="_blank">By placing the noodles in a special machine</a> built for the task and recording the bending with a high-powered camera, the young scientists were able to observe in extreme detail exactly what each change in their snapping method did to the pasta. After breaking more than 500 noodles, they found the solution.</p>
The apparatus the MIT researchers built specifically for the task of snapping hundreds of spaghetti sticks.
(Courtesy of the researchers)
What possible application could this have?<p>The snapback effect is not limited to uncooked pasta noodles and can be applied to rods of all sorts. The discovery of how to cleanly break them in two could be applied to future engineering projects.</p><p>Likewise, knowing how things fragment and fail is always handy to know when you're trying to build things. Carbon Nanotubes, <a href="https://bigthink.com/ideafeed/carbon-nanotube-space-elevator" target="_self">super strong cylinders often hailed as the building material of the future</a>, are also rods which can be better understood thanks to this odd experiment.</p><p>Sometimes big discoveries can be inspired by silly questions. If it hadn't been for Richard Feynman bending noodles seventy years ago, we wouldn't know what we know now about how energy is dispersed through rods and how to control their fracturing. While not all silly questions will lead to such a significant discovery, they can all help us learn.</p>
What happens if we consider welfare programs as investments?
- A recently published study suggests that some welfare programs more than pay for themselves.
- It is one of the first major reviews of welfare programs to measure so many by a single metric.
- The findings will likely inform future welfare reform and encourage debate on how to grade success.
Welfare as an investment<p>The <a href="https://scholar.harvard.edu/files/hendren/files/welfare_vnber.pdf" target="_blank">study</a>, carried out by Nathaniel Hendren and Ben Sprung-Keyser of Harvard University, reviews 133 welfare programs through a single lens. The authors measured these programs' "Marginal Value of Public Funds" (MVPF), which is defined as the ratio of the recipients' willingness to pay for a program over its cost.</p><p>A program with an MVPF of one provides precisely as much in net benefits as it costs to deliver those benefits. For an illustration, imagine a program that hands someone a dollar. If getting that dollar doesn't alter their behavior, then the MVPF of that program is one. If it discourages them from working, then the program's cost goes up, as the program causes government tax revenues to fall in addition to costing money upfront. The MVPF goes below one in this case. <br> <br> Lastly, it is possible that getting the dollar causes the recipient to further their education and get a job that pays more taxes in the future, lowering the cost of the program in the long run and raising the MVPF. The value ratio can even hit infinity when a program fully "pays for itself."</p><p> While these are only a few examples, many others exist, and they do work to show you that a high MVPF means that a program "pays for itself," a value of one indicates a program "breaks even," and a value below one shows a program costs more money than the direct cost of the benefits would suggest.</p> After determining the programs' costs using existing literature and the willingness to pay through statistical analysis, 133 programs focusing on social insurance, education and job training, tax and cash transfers, and in-kind transfers were analyzed. The results show that some programs turn a "profit" for the government, mainly when they are focused on children:
This figure shows the MVPF for a variety of polices alongside the typical age of the beneficiaries. Clearly, programs targeted at children have a higher payoff.
Nathaniel Hendren and Ben Sprung-Keyser<p>Programs like child health services and K-12 education spending have infinite MVPF values. The authors argue this is because the programs allow children to live healthier, more productive lives and earn more money, which enables them to pay more taxes later. Programs like the preschool initiatives examined don't manage to do this as well and have a lower "profit" rate despite having decent MVPF ratios.</p><p>On the other hand, things like tuition deductions for older adults don't make back the money they cost. This is likely for several reasons, not the least of which is that there is less time for the benefactor to pay the government back in taxes. Disability insurance was likewise "unprofitable," as those collecting it have a reduced need to work and pay less back in taxes. </p>
What are the implications of all this?<div class="rm-shortcode" data-media_id="ceXv4XLv" data-player_id="FvQKszTI" data-rm-shortcode-id="3b407f5aa043eeb84f2b7ff82f97dc35"> <div id="botr_ceXv4XLv_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/ceXv4XLv-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/ceXv4XLv-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/ceXv4XLv-FvQKszTI.js"></script> </div> <p>Firstly, it shows that direct investments in children in a variety of areas generate very high MVPFs. Likewise, the above chart shows that a large number of the programs considered pay for themselves, particularly ones that "invest in human capital" by promoting education, health, or similar things. While programs that focus on adults tend to have lower MVPF values, this isn't a hard and fast rule.</p><p>It also shows us that very many programs don't "pay for themselves" or even go below an MVPF of one. However, this study and its authors do not suggest that we abolish programs like disability payments just because they don't turn a profit.</p><p>Different motivations exist behind various programs, and just because something doesn't pay for itself isn't a definitive reason to abolish it. The returns on investment for a welfare program are diverse and often challenging to reckon in terms of money gained or lost. The point of this study was merely to provide a comprehensive review of a wide range of programs from a single perspective, one of dollars and cents. </p><p>The authors suggest that this study can be used as a starting point for further analysis of other programs not necessarily related to welfare. </p><p>It can be difficult to measure the success or failure of a government program with how many metrics you have to choose from and how many different stakeholders there are fighting for their metric to be used. This study provides us a comprehensive look through one possible lens at how some of our largest welfare programs are doing. </p><p>As America debates whether we should expand or contract our welfare state, the findings of this study offer an essential insight into how much we spend and how much we gain from these programs. </p>
Finding a balance between job satisfaction, money, and lifestyle is not easy.
- When most of your life is spent doing one thing, it matters if that thing is unfulfilling or if it makes you unhappy. According to research, most people are not thrilled with their jobs. However, there are ways to find purpose in your work and to reduce the negative impact that the daily grind has on your mental health.
- "The evidence is that about 70 percent of people are not engaged in what they do all day long, and about 18 percent of people are repulsed," London Business School professor Dan Cable says, calling the current state of work unhappiness an epidemic. In this video, he and other big thinkers consider what it means to find meaning in your work, discuss the parts of the brain that fuel creativity, and share strategies for reassessing your relationship to your job.
- Author James Citrin offers a career triangle model that sees work as a balance of three forces: job satisfaction, money, and lifestyle. While it is possible to have all three, Citrin says that they are not always possible at the same time, especially not early on in your career.