from the world's big
Confirmed: The Milky Way's monstrous black hole
A young star and a belt of gasses give the game away.
- Scientists have provided the first confirmation that what's at the center of the Milky Way is a supermassive black hole.
- The discovery caught the interaction of gasses and a small star spinning around the mysterious object.
- This is thought to be compelling proof of the black hole's central role in a galaxy.
At the center of the Milky Way, about 25,000 light years away, is a faint source of radio noise. It's huge, estimated to weigh the equivalent of the 4.14 million suns. Astronomers have long suspected it's a supermassive black hole, and they've named it "Sagittarius A*." This week, the European Southern Observatory (ESO) announced that an international collaboration led by Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics (MPE) has collected the most definitive proof that this is exactly what Sagittarius A* is.
While astronomers can't directly observe a black hole — light doesn't escape it — they might, however, be able to see some of what goes on around one. Genzel and other scientists across the globe collected information regarding a small star called "S2" and the belt of gas, or accretion disc, that spin around Sagittarius A*. It's in the interaction between the two that the new discovery lies, and it was made possible by a breakthrough in imaging.
The imaging breakthrough
Photo credit: MPE/GRAVITY team
The ESO has a four-telescope array, the Very Large Telescope (VLT) of the Paranal Observatory, rising 2635 meters above sea level in Chile's Atacama Desert. The amazing device that ultimately allowed the team to confirm Sagittarius A*'s identity leverages the Paranal telescopes. It's called "GRAVITY," and it combines all four in a single interferometer that has the resolution of a single mirror resolution of a single mirror 130 meters in diameter. "All of the sudden, we can see 1,000 times fainter than before," said Genzel when GRAVITY went into use.
S2 and the redshift
Image source: ESO/MPE/S. Gillessen
Every 16 years, a young blue star dubbed "S2" or S-02"completes an elongated orbit that brings it perilously close to Sagittarius A*, about 11 billion miles.
Many scientists feel that black holes — of which Einstein himself was unconvinced — are predicted by general relativity. (They were only finally confirmed a couple of years back when two black holes collided.) Einstein's theory, though, also predicts that if S2 is indeed orbiting a black hole, the speed of the light waves bouncing off it when it draws Sagittarius A*near should slow down, shifting the light it reflects to a more reddish hue.
In July of this year, Genzel's team announced that they had observed via GRAVITY the center of the Milky Way, and had seen the predicted redshift, allowing them to pinpoint S2's closest approach to Sagittarius A*. New York Times reports that as the results were being read off at the Munich announcement, the room broke out into applause.
Accretion disc flares
Also spinning around Sagittarius A* is an accretion disc that travels at nearly 30 percent the speed of light, zooming 150 million miles around the object every 45 minutes. According to relativity, whenever S2 — or any hot object — reaches its innermost, or stable, orbit, bits of it should cross the event horizon and be instantly vaporized as they fall into the black hole, sparking brief infrared flares.
Thanks to GRAVITY, the MPE scientists have been able to see that this actually happens at S2's closest fly-by. "GRAVITY's tremendous sensitivity has allowed us to observe the accretion processes in real time in unprecedented detail," another MPR scientist, Oliver Pfuhl, tells ESO. "It's mind-boggling to actually witness material orbiting a massive black hole at 30 percent of the speed of light."
The predicted flares were spotted, actually, as the MPE team was observing S2 in the research that led to July's announcement, though it took until now to prepare supporting materials for publication. "We were closely monitoring S2, and of course we always keep an eye on Sagittarius A*," Pfuhl recalls. "During our observations, we were lucky enough to notice three bright flares from around the black hole — it was a lucky coincidence!"
Now we know what lies at the center of the Milky Way
Image source: ESO
Genzel refers to the discovery of the flares as a "resounding confirmation of the massive black hole paradigm." Astronomers believe that black holes likely lie at the core of other galaxies as well, so this announcement has far-reaching implications. "This always was one of our dream projects but we did not dare to hope that it would become possible so soon," he concludes.
- Scientists observe strange lights in the heart of the Milky Way - Big Think ›
- A supercomputer explains supermassive black holes - Big Think ›
Higher education faces challenges that are unlike any other industry. What path will ASU, and universities like ASU, take in a post-COVID world?
- Everywhere you turn, the idea that coronavirus has brought on a "new normal" is present and true. But for higher education, COVID-19 exposes a long list of pernicious old problems more than it presents new problems.
- It was widely known, yet ignored, that digital instruction must be embraced. When combined with traditional, in-person teaching, it can enhance student learning outcomes at scale.
- COVID-19 has forced institutions to understand that far too many higher education outcomes are determined by a student's family income, and in the context of COVID-19 this means that lower-income students, first-generation students and students of color will be disproportionately afflicted.
What conditions of the new normal were already appreciated widely?<p>First, we understand that higher education is unique among industries. Some industries are governed by markets. Others are run by governments. Most operate under the influence of both markets and governments. And then there's higher education. Higher education as an "industry" involves public, private, and for-profit universities operating at small, medium, large, and now massive scales. Some higher education industry actors are intense specialists; others are adept generalists. Some are fantastically wealthy; others are tragically poor. Some are embedded in large cities; others are carefully situated near farms and frontiers.</p> <p>These differences demonstrate just some of the complexities that shape higher education. Still, we understand that change in the industry is underway, and we must be active in directing it. Yet because of higher education's unique (and sometimes vexing) operational and structural conditions, many of the lessons from change management and the science of industrial transformation are only applicable in limited or highly modified ways. For evidence of this, one can look at various perspectives, including those that we have offered, on such topics as <a href="https://www.insidehighered.com/digital-learning/blogs/rethinking-higher-education/lessons-disruption" target="_blank">disruption</a>, <a href="https://www.nytimes.com/2020/02/20/education/learning/education-technology.html" target="_blank">technology management</a>, and so-called "<a href="https://www.insidehighered.com/sites/default/server_files/media/Excerpt_IHESpecialReport_Growing-Role-of-Mergers-in-Higher-Ed.pdf" target="_blank">mergers and acquisitions</a>" in higher education. In each of these spaces, the "market forces" and "market rules" for higher education are different than they are in business, or even in government. This has always been the case and it is made more obvious by COVID-19.</p> <p>Second, with so much excitement about innovation in higher education, we sometimes lose sight of the fact that students are—and should remain—the core cause for innovation. Higher education's capacity to absorb new ideas is strong. But the ideas that endure are those designed to benefit students, and therefore society. This is important to remember because not all innovations are designed with students in mind. The recent history of innovation in higher education includes several cautionary tales of what can happen when institutional interests—or worse, <a href="https://www.insidehighered.com/news/2016/02/09/apollos-new-owners-seek-fresh-start-beleaguered-company" target="_blank">shareholder</a> interests—are placed above student well-being.</p>
Photo: Getty Images<p>Third, it is abundantly apparent that universities must leverage technology to increase educational quality and access. The rapid shift to delivering an education that complies with social distancing guidelines speaks volumes about the adaptability of higher education institutions, but this transition has also posed unique difficulties for colleges and universities that had been slow to adopt digital education. The last decade has shown that online education, implemented effectively, can meet or even surpass the quality of in-person <a href="https://link-springer-com.ezproxy1.lib.asu.edu/article/10.1007/s10639-019-10027-z" target="_blank">instruction</a>.</p><p>Digital instruction, broadly defined, leverages online capabilities and integrates adaptive learning methodologies, predictive analytics, and innovations in instructional design to enable increased student engagement, personalized learning experiences, and improved learning outcomes. The ability of these technologies to transcend geographic barriers and to shrink the marginal cost of educating additional students makes them essential for delivering education at scale.</p><p>As a bonus, and it is no small thing given that they are the core cause for innovation, students embrace and enjoy digital instruction. It is their preference to learn in a format that leverages technology. This should not be a surprise; it is now how we live in all facets of life.</p><p>Still, we have only barely begun to conceive of the impact digital education will have. For example, emerging virtual and augmented reality technologies that facilitate interactive, hands-on learning will transform the way that learners acquire and apply new knowledge. Technology-enabled learning cannot replace the traditional college experience or ensure the survival of any specific college, but it can enhance student learning outcomes at scale. This has always been the case, and it is made more obvious by COVID-19.</p>
What conditions of the new normal were emerging suspicions?<p>Our collective thinking about the role of institutional or university-to-university collaboration and networking has benefitted from a new clarity in light of COVID-19. We now recognize more than ever that colleges and universities must work together to ensure that the American higher education system is resilient and sufficiently robust to meet the needs of students and their families.</p> <p>In recent weeks, various commentators have suggested that higher education will face a wave of institutional <a href="https://www.businessinsider.com/scott-galloway-predicts-colleges-will-close-due-to-pandemic-2020-5" target="_blank">closures</a> and consolidations and that large institutions with significant online instruction capacity will become dominant.</p> <p>While ASU is the largest public university in the United States by enrollment and among the most well-equipped in online education, we strongly oppose "let them fail" mindsets. The strength of American higher education relies on its institutional diversity, and on the ability of colleges and universities to meet the needs of their local communities and educate local students. The needs of learners are highly individualized, demanding a wide range of options to accommodate the aspirations and learning styles of every kind of student. Education will become less relevant and meaningful to students, and less responsive to local needs, if institutions of higher learning are allowed to fail. </p> <p>Preventing this outcome demands that colleges and universities work together to establish greater capacity for remote, distributed education. This will help institutions with fewer resources adapt to our new normal and continue to fulfill their mission of serving students, their families, and their communities. Many had suspected that collaboration and networking were preferable over letting vulnerable colleges fail. COVID-19's new normal seems to be confirming this.</p>
President Barack Obama delivers the commencement address during the Arizona State University graduation ceremony at Sun Devil Stadium May 13, 2009 in Tempe, Arizona. Over 65,000 people attended the graduation.
Photo by Joshua Lott/Getty Images<p>A second condition of the new normal that many had suspected to be true in recent years is the limited role that any one university or type of university can play as an exemplar to universities more broadly. For decades, the evolution of higher education has been shaped by the widespread imitation of a small number of elite universities. Most public research universities could benefit from replicating Berkeley or Michigan. Most small private colleges did well by replicating Williams or Swarthmore. And all universities paid close attention to Harvard, Princeton, MIT, Stanford, and Yale. It is not an exaggeration to say that the logic of replication has guided the evolution of higher education for centuries, both in the US and abroad.</p><p>Only recently have we been able to move beyond replication to new strategies of change, and COVID-19 has confirmed the legitimacy of doing so. For example, cases such as <a href="https://www.washingtonpost.com/education/2020/03/10/harvard-moves-classes-online-advises-students-stay-home-after-spring-break-response-covid-19/" target="_blank">Harvard's</a> eviction of students over the course of less than one week or <a href="https://www.nhregister.com/news/coronavirus/article/Mayor-New-Haven-asks-for-coronavirus-help-Yale-15162606.php" target="_blank">Yale's apparent reluctance</a> to work with the city of New Haven, highlight that even higher education's legacy gold standards have limits and weaknesses. We are hopeful that the new normal will include a more active and earnest recognition that we need many types of universities. We think the new normal invites us to rethink the very nature of "gold standards" for higher education.</p>
A graduate student protests MIT's rejection of some evacuation exemption requests.
Photo: Maddie Meyer/Getty Images<p>Finally, and perhaps most importantly, we had started to suspect and now understand that America's colleges and universities are among the many institutions of democracy and civil society that are, by their very design, incapable of being sufficiently responsive to the full spectrum of modern challenges and opportunities they face. Far too many higher education outcomes are determined by a student's family income, and in the context of COVID-19 this means that lower-income students, first-generation students and students of color will be disproportionately afflicted. And without new designs, we can expect postsecondary success for these same students to be as elusive in the new normal, as it was in the <a href="http://pellinstitute.org/indicators/reports_2019.shtml" target="_blank">old normal</a>. This is not just because some universities fail to sufficiently recognize and engage the promise of diversity, this is because few universities have been designed from the outset to effectively serve the unique needs of lower-income students, first-generation students and students of color.</p>
Where can the new normal take us?<p>As colleges and universities face the difficult realities of adapting to COVID-19, they also face an opportunity to rethink their operations and designs in order to respond to social needs with greater agility, adopt technology that enables education to be delivered at scale, and collaborate with each other in order to maintain the dynamism and resilience of the American higher education system.</p> <p>COVID-19 raises questions about the relevance, the quality, and the accessibility of higher education—and these are the same challenges higher education has been grappling with for years. </p> <p>ASU has been able to rapidly adapt to the present circumstances because we have spent nearly two decades not just anticipating but <em>driving</em> innovation in higher education. We have adopted a <a href="https://www.asu.edu/about/charter-mission-and-values" target="_blank">charter</a> that formalizes our definition of success in terms of "who we include and how they succeed" rather than "<a href="https://www.washingtonpost.com/opinions/2019/10/17/forget-varsity-blues-madness-lets-talk-about-students-who-cant-afford-college/" target="_blank">who we exclude</a>." We adopted an entrepreneurial <a href="https://president.asu.edu/read/higher-logic" target="_blank">operating model</a> that moves at the speed of technological and social change. We have launched initiatives such as <a href="https://www.instride.com/how-it-works/" target="_blank">InStride</a>, a platform for delivering continuing education to learners already in the workforce. We developed our own robust technological capabilities in ASU <a href="https://edplus.asu.edu/" target="_blank">EdPlus</a>, a hub for research and development in digital learning that, even before the current crisis, allowed us to serve more than 45,000 fully online students. We have also created partnerships with other forward-thinking institutions in order to mutually strengthen our capabilities for educational accessibility and quality; this includes our role in co-founding the <a href="https://theuia.org/" target="_blank">University Innovation Alliance</a>, a consortium of 11 public research universities that share data and resources to serve students at scale. </p> <p>For ASU, and universities like ASU, the "new normal" of a post-COVID world looks surprisingly like the world we already knew was necessary. Our record breaking summer 2020 <a href="https://asunow.asu.edu/20200519-sun-devil-life-summer-enrollment-sets-asu-record" target="_blank">enrollment</a> speaks to this. What COVID demonstrates is that we were already headed in the right direction and necessitates that we continue forward with new intensity and, we hope, with more partners. In fact, rather than "new normal" we might just say, it's "go time." </p>
Russian astrophysicists propose the Casimir Effect causes the universe's expansion to accelerate.
- Astrophysicists from Russia propose a theory that says dark energy doesn't exist.
- Instead, the scientists think the Casimir Effect creates repulsion.
- This effect causes the expansion of the universe to accelerate.
Gravity Should Slow the Expanding Universe, but Dark Energy Is Speeding It ...<div class="rm-shortcode" data-media_id="TXFqpm0M" data-player_id="FvQKszTI" data-rm-shortcode-id="e242a06f4b4464e0cffae45d5142d2ea"> <div id="botr_TXFqpm0M_FvQKszTI_div" class="jwplayer-media" data-jwplayer-video-src="https://content.jwplatform.com/players/TXFqpm0M-FvQKszTI.js"> <img src="https://cdn.jwplayer.com/thumbs/TXFqpm0M-1920.jpg" class="jwplayer-media-preview" /> </div> <script src="https://content.jwplatform.com/players/TXFqpm0M-FvQKszTI.js"></script> </div>
Sallie Krawcheck and Bob Kulhan will be talking money, jobs, and how the pandemic will disproportionally affect women's finances.
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