Six solar system oddities and why we must learn about them
Want some crazy space phenomena? You don't have to leave the neighborhood for it.
13 October, 2020
By nagualdesign; Tom Ruen, background taken from File:ESO - Milky Way.jpg - Own work, CC BY-SA 4.0
- The universe has a lot of weird stuff in it.
- You don't have to travel far to find it. Our solar system is filled with oddities and strangeness. Some that we can't figure out.
- Learning about these things isn't just fun, it can be applied to our lives and can alter our perspectives.
<p>It has been said that the universe is "not only stranger than we imagine, but that it is stranger than we <em>can </em>imagine." John Haldane, the originator of that quote (slightly different wording according to some <a href="https://quoteinvestigator.com/2018/12/25/universe/" target="_blank">sources</a>), might have been more correct than he knew. Since his death, we've discovered such exotic objects as <a href="https://en.wikipedia.org/wiki/Pulsar" target="_blank">pulsars</a> and the<a href="https://en.wikipedia.org/wiki/Cosmic_microwave_background" target="_blank"> cosmic background radiation</a>. Even more out there, scientists have postulated the existence of stuff as bizarre as <a href="https://en.wikipedia.org/wiki/Cosmic_microwave_background" target="_blank">dark matter,</a> <a href="https://en.wikipedia.org/wiki/Dark_energy" target="_blank">dark energy</a>, and the aptly named "<a href="https://en.wikipedia.org/wiki/Strange_matter" target="_blank">strange matter.</a>"<br> <br> One doesn't even need to leave the solar system to find oddities. Last week, we discussed Saturn's hexagonal <a href="https://bigthink.com/surprising-science/saturn-hexagon-storm" target="_blank">storm</a>; today, we'll look at six of the strangest things in our cosmic backyard and consider why time spent investigating them is not time wasted.</p>
Mercury ain't what it used to be
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDUxMjg1NS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1OTMwMTQwMH0.BQTUzYP44Yp6mAWhh3iLfXBny2OU53oaZMeWghFPld0/img.jpg?width=980" id="a9983" class="rm-shortcode" data-rm-shortcode-id="5d4f2fcffc24bd62fc10a89379cb1c17" data-rm-shortcode-name="rebelmouse-image" alt="Mercury" />False color image of Mercury (the yellow is water ice).
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
<p> The smallest planet in the solar system constantly outdoes itself. Mercury is <a href="https://www.nasa.gov/feature/the-incredible-shrinking-mercury-is-active-after-all" target="_blank" rel="noopener noreferrer">shrinking</a>. <strong></strong><br> </p><p> Unlike many other items on this list, this strange occurrence is likely caused by a fairly mundane mechanism. As the planet, which is made primarily of metal, has a high iron content, scientists speculate that the planet is shrinking as it continues to cool down from the high internal temperatures it had when it formed. <br> <br> However, this isn't the end of things. Why Mercury has such a higher iron content remains a mystery. A leading hypothesis is that the planet used to be much larger, but that many of its non-metallic components were knocked away by an impact with a <a href="https://zenodo.org/record/1253898#.X4W9A5pOlH4" target="_blank" rel="noopener noreferrer">planetoid</a> or that spikes in the sun's temperature caused much of the rocky crust of Mercury to vaporize and blow away, leaving an iron core. </p>You can spin faster than Venus, if you try.
<iframe width="730" height="430" src="https://www.youtube.com/embed/dXOLJOnLKDg" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><p> As seen from Earth, the sun comes up in the east and sets in the west. On Venus, the opposite is <a href="https://coolcosmos.ipac.caltech.edu/ask/50-Does-Venus-really-spin-backwards-" target="_blank" rel="noopener noreferrer">true</a>. This is unique among the planets of the Solar System. Even stranger, it would take 243 Earth days to be able to enjoy another sunrise if you could see it from Venus' surface. The planet only rotates at a leisurely 6.52 km/h (4.05 mph), compare that to Earth's 674.4 km/h (1,040.4 mph). For comparison, a Venusian year is only 225 Earth days, meaning a year there is shorter than a day!<strong></strong></p><p><strong> </strong>The slow rotation speed causes side effects you might not have suspected. While the Earth's rotation causes the center to bulge out somewhat, Venus lacks this and is much closer to being spherical.</p><p>A variety of theories attempting to explain all this have been advanced. One argues that this results from the sun's tidal forces in battle with those created by the thick Venusian atmosphere, with the former slowing rotation and the later speeding it up. An amusing hypothesis argues that the whole planet was somehow flipped upside down, and it continues to spin in the same direction as <a href="https://www.scientificamerican.com/article/why-venus-spins-the-wrong/" target="_blank" rel="noopener noreferrer">it always has</a>. Another suggests that a massive impact, early in the Solar System's history, knocked Venus so hard it started spinning <a href="https://amazingsciencefacts.com/why-does-venus-spin-backwards/" target="_blank" rel="noopener noreferrer">backward</a>. </p><p> This last theory has the bonus of explaining why Venus has no moons, as the resulting powerful tidal forces would have caused any moon there to fall into the <a href="https://en.wikipedia.org/wiki/Tidal_acceleration#Tidal_deceleration" target="_blank" rel="noopener noreferrer">planet</a>. </p>Everything about Saturn’s moon Iapetus is odd
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDUxMjg1Ni9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyMTc5NDI4MH0.FqgD7t6r6Oeq1GgnEmJwDhWCYoxQ7MQ_o9vipHfIUCY/img.jpg?width=980" id="5c830" class="rm-shortcode" data-rm-shortcode-id="a1c8712b303d4e24243ba9bfdb4cfdcd" data-rm-shortcode-name="rebelmouse-image" alt="lapetus" />Images of Iapetus' mysterious ridge taken by Cassini.
(Public Domain)
Uranus is a bit crooked
<iframe width="730" height="430" src="https://www.youtube.com/embed/8GqnzBJkWcw" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><p> If you remember anything from grade school astronomy about <a href="https://en.wikipedia.org/wiki/Uranus" target="_blank" rel="noopener noreferrer">Uranus</a>, it's probably that it rolls along its side like a ball while the other planets spin like tops. Its poles each spend the solstice either in full sunlight or total darkness. It is only during the equinox, when the poles are oriented perpendicular to the sun, that the entire planet has a day and night cycle similar to the other planets.</p><p>Why it rolls like this is unknown. The current leading theory involves what seems to be the favorite explanation of astronomers, a large object knocking into the planet in the early days of the solar system. As you might expect, this orientation means that Uranus's poles get more sunlight and heat than the equator does. Despite this, the equator is still warmer than the poles are. The cause of this is currently also unknown. </p>Neptune radiates heat. Like, a lot of heat.
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDUxMjkxMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxNDI0NDU4NH0.cbSmAN0vbiKgxamZPbwsUq7RgCzy24WkwgVxq-iERgQ/img.jpg?width=1245&coordinates=0%2C59%2C0%2C66&height=700" id="e98ec" class="rm-shortcode" data-rm-shortcode-id="939ae4cf6968960db278461e81435b7e" data-rm-shortcode-name="rebelmouse-image" alt="Neptune" />A slightly retouched image of Neptune's south pole as seen by Voyager 2.
By Kevin Gill from Los Angeles, CA, United States - Neptune - August 25 1989, CC BY-SA 2.0,
<p> The most distant known planet from the sun (sorry Pluto), Neptune gets a tiny fraction of the heat and light that other planets enjoy. It gets less than half as much sunlight as its neighbor, Uranus. As they say, though, it's what's on the inside that counts. Neptune radiates a substantial amount of heat, 2.6 times as much as it gets from the Sun, compared to Uranus' 1.1 times as much. <br> <br> This internal heating provides the energy needed for Neptune to have the fastest winds in the solar system, with gusts of up to 2,100 km/h (1,300 mph) observed. <br> <br> Some scientists propose the heat is just leftover from the planet's <a href="https://www.space.com/something-strange-inside-neptune.html" target="_blank" rel="noopener noreferrer">formation</a>. Others suggest that the ice giants' internal heating might be cyclical, with Neptune and Uranus being out of sync with each other. It is also possible to view Uranus as the strange one, arguing that its internal heating is much lower than it should be. Theories that go this way often suggest that whatever knocked Uranus over took a fair amount of heat with it. The trouble with any hypothesis advanced is that it has to deal with Neptune and Uranus' apparent similarities while also allowing for this single, tremendous difference. </p>There is a Planet Nine, probably, maybe.
<iframe width="730" height="430" src="https://www.youtube.com/embed/7rjURtq1pNI" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><p> Neptune was discovered after Uranus' orbit was observed to differ from predictions in a way that suggested a large object was influencing it. Neptune was discovered orbiting almost exactly where such a large object was expected to be. Today, a similar problem exists with some objects in the Kuiper belt, leading some scientists to argue for the existence of a "<a href="https://en.wikipedia.org/wiki/Planet_Nine" target="_blank" rel="noopener noreferrer">Planet Nine</a>," exerting an influence on their orbits.</p><p>Some Trans-Neptunian Objects (TNOs) have clustered orbits. Seen from above, the long ellipses that track their orbits tend to nest inside one another, with their vertexes all pointing in the same direction. Typically, we would expect these orbits to be distributed more <a href="https://www.space.com/does-planet-nine-exist.html" target="_blank" rel="noopener noreferrer">randomly</a>. The odds that they would be in the configuration we see them in due to chance are extremely low. </p><p> However, a planet around ten times the Earth's size in an extremely eccentric, far-flung orbit would exert a gravitational pull just strong enough to cause this and other strange phenomena observed in the Kuiper Belt. </p><p> Alternative explanations for the observed data exist. They range from the mundane proposal that what we see is coincidentally similar to what a planet would cause, to the exotic notion that we should be looking for <a href="https://arxiv.org/abs/1909.11090" target="_blank" rel="noopener noreferrer">small black holes </a>rather than a planet. No Planet Nine has been spotted, but various studies have not yet ruled out the possibility of its existence. </p>Why is any of this important?
<iframe width="730" height="430" src="https://www.youtube.com/embed/qPvSRPsWhOQ" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><p> Understanding how these odd phenomena came into existence can give us a better understanding of the formation of the solar system in general and the planets in particular. Having a good idea of where something is coming from is very helpful in science, as it can make it easier to estimate where it is going. </p><p>That can be very nice to have when you're talking about the rock with odd fitting continents, exploding mountains, and an ever-evolving atmosphere floating in space you're sitting on. Beyond that, many people hope that humans will travel to other bodies in the solar system someday. It might be nice to know a bit about the strange places we might end up traveling to or some of the things we might encounter before heading out. <br> <br> Even if we don't ever get to Neptune or Planet Nine, studying the odd parts of the solar system can serve as a reminder of how big and how strange the universe we live in really is. Our changing understanding of the universe has impacted how we live our lives before, and more than a few great thinkers pointed to changes in our understanding of <a href="http://www.themcclungs.net/astronomy/people/aristotle.html" target="_blank">astronomy</a> to justify and explain their thinking in other <a href="https://en.wikipedia.org/wiki/Copernican_Revolution#Immanuel_Kant" target="_blank">fields</a>. <br> <br> Plus, given how many of these oddities seem related to things getting hit with giant rocks, these discoveries might help us finally get around to deciding what to do if an asteroid comes our way. </p>
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Scientists may have solved the mystery of how the moon was magnetized
New research explains why the Moon's crust is magnetized by debunking one long-standing theory.
12 October, 2020
Credit: Science Advances, doi: 10.1126/sciadv.abb1475
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<p>The mystery of how the Moon got a magnetic field and what happened to it has baffled scientists for decades. New research explains why the Moon's crust is magnetized by debunking one long-standing theory.</p><p>While the Moon doesn't currently have a global magnetic field, analysis of rocks gathered by Apollo astronauts suggested that it used to be strongly magnetized about 3.56 to 4.25 billion years ago. As some of the rocks were magnetic, scientists estimated that parts of the lunar crust still exhibit traces of magnetization for hundreds of miles. </p><p>The new study's co-author, Australian researcher Dr. Katarina Miljkovic, from the Curtin Space Science and Technology Centre at Curtin University, sees their work as a continuation of efforts by previous scientists:</p><p style="margin-left: 20px;">"There are two long term hypotheses associated with why the Moon's crust might be magnetic: One is that the magnetisation is the result of an ancient dynamo in the lunar core, and the other is that it's the result of an amplification of the interplanetary magnetic field, created by meteoroid impacts," Dr. Miljkovic shared in a <a href="https://news.curtin.edu.au/media-releases/moons-magnetic-crust-research-sees-scientists-debunk-long-held-theory/" target="_blank">press release.</a></p>
<p>The research her team carried out is a "deep numerical study" that looks at the theory that the magnetization is influenced by impacts and essentially disproves it. Dr. Miljkovic says the collisions were not responsible because they "found that meteoroid impact plasmas interact much more weakly with the Moon compared to the magnetisation levels obtained from the lunar crust." As such, the scientists concluded that the core dynamo is the "the only plausible source of the magnetisation of the Moon's crust."</p><p>Dr. Miljkovic's research involved calculating the mass and thermal energy of the vapor generated during violent impacts about 4 billion years ago, as evidenced by the craters we can see just by looking up at night.</p>
Moon mission 2.0: What humanity will learn by going back to the Moon | Michelle Thaller | Big Think
<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="c97eca7a853afe3bcf42f075bd85b43c"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/4vAiCSTV9lQ?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p><span style="background-color: initial;">Dr. Rona Oran, </span><span style="background-color: initial;">the lead researcher of the study, from the Massachusetts Institute of Technology (MIT), said that modern computing power allowed them to run impact and plasma simulations that were previously impossible to carry out. This also allowed them to rule out ideas.</span></p><p style="margin-left: 20px;">"In addition to the Moon, Mercury, some meteorites, and other small planetary bodies all have a magnetic crust," <a href="https://news.curtin.edu.au/media-releases/moons-magnetic-crust-research-sees-scientists-debunk-long-held-theory/" target="_blank">stated Dr. Oran.</a> "Perhaps other equivalent mechanical dynamo mechanisms, such as those we now believe to have been in operation on the Moon, could have been in effect on these objects as well."</p><p>Check out the study published by <a href="https://advances.sciencemag.org/content/6/40/eabb1475" target="_blank">Science Advances.</a></p>
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The universe keeps dying and being reborn, claims Nobel Prize winner
Sir Roger Penrose claims our universe has been through multiple Big Bangs, with more coming.
09 October, 2020
Credit: Adobe Stock
- Roger Penrose, the 2020 Nobel Prize winner in physics, claims the universe goes through cycles of death and rebirth.
- According to the scientist, there have been multiple Big Bangs, with more on the way.
- Penrose claims that black holes hold clues to the existence of previous universes.
<p>Sir Roger Penrose, a mathematician and physicist from the University of Oxford who has just shared this year's Nobel Prize in physics, claims our universe has gone through multiple Big Bangs, with another one coming in our future.</p><p>Penrose received the Nobel for his working out mathematical methods that proved and expanded Albert Einstein's general theory of relativity, and for his discoveries on black holes, which showed how objects that become too dense undergo gravitational collapse into <em>singularities</em> – points of infinite mass. </p><p>As he accepted the Prize, Penrose reiterated his belief in what he called "a crazy theory of mine" that the universe will expand until all matter will ultimately decay. And then a new Big Bang will bring a new universe into existence.</p><p style="margin-left: 20px;">"The Big Bang was not the beginning," Penrose said in an <a href="https://www.telegraph.co.uk/news/2020/10/06/earlier-universe-existed-big-bang-can-observed-today/" target="_blank">interview</a> with The Telegraph<em>.</em> "There was something before the Big Bang and that something is what we will have in our future."</p>
<p>What proof does the physicist have for this theory he dubbed "<a href="https://physicsworld.com/a/inside-penroses-universe/" target="_blank">conformal cyclic cosmology</a>" (CCC) that goes against the current Big Bang dogma? He said he discovered six "warm" sky points (called "Hawking Points") which are all about eight times larger than the diameter of the Moon. The late Professor Stephen Hawking, whose name they bear, proposed that black holes "leak" radiation and would eventually evaporate. As this might take longer than the age of the universe we are currently inhabiting (13.77 billion years old), spotting such holes is very unlikely.</p><p>Penrose (89), who collaborated with Hawking, thinks that we are, in fact, able to observe "dead" black holes left by previous universes or "aeons". If proven correct, this would also validate Hawking's theories. </p><p>The physicist's <a href="https://academic.oup.com/mnras/article-abstract/495/3/3403/5838759" target="_blank">2020 paper</a>, published in the Monthly Notices of the Royal Astronomical Society<em>, </em>offers evidence of "anomalous circular spots" in the cosmic microwave background (CMB) that have raised temperatures. The data revealing the spots came from <em>Planck</em> 70 GHz satellite and was confirmed by up to 10,000 simulations.</p>
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ3OTQ4MC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNDk0NDEzMH0.GcLV8x_ctTTYymT2whD9sycdDArlNWsQ4OsN9O7qW4A/img.jpg?width=980" id="8fa68" class="rm-shortcode" data-rm-shortcode-id="ad98fc78f930ba2b0e56906c6010cf59" data-rm-shortcode-name="rebelmouse-image" />
Hot spots in Planck CMB data.
Credit: ESA and the Planck Collaboration
<p><span style="background-color: initial;">Penrose's <a href="https://physicsworld.com/a/new-evidence-for-cyclic-universe-claimed-by-roger-penrose-and-colleagues/" target="_blank">2018 paper</a> pinpointed radiation hot spots in the CMB as possibly being produced by evaporating black holes. A <a href="https://physicsworld.com/a/penrose-claims-to-have-glimpsed-universe-before-big-bang/" target="_blank" rel="noopener noreferrer">2010 paper</a> by Penrose and </span><span style="background-color: initial;">Vahe Gurzadyan from the Yerevan Physics Institute in Armenia found support for cyclic cosmology in the uniform temperature rings within the CMB. The scientists proposed then that the rings were caused by signatures of gravitational waves from colliding black holes in a universe that preceded ours.</span></p><p>These ideas are controversial within the cosmologist community, with some pointing to the difficulty of conforming an infinitely big universe in one aeon to a super-small one in the next. This would necessitate making all particles lose mass as the universe gets old.</p><p>Check out <a href="https://accelconf.web.cern.ch/e06/PAPERS/THESPA01.PDF" target="_blank">Penrose's most recent paper,</a> titled "Apparent evidence for Hawking points in the CMB Sky" <a href="https://academic.oup.com/mnras/article-abstract/495/3/3403/5838759" target="_blank">here</a>.</p><p>For another fascinating Penrose theory, <a href="https://bigthink.com/paul-ratner/why-a-genius-scientist-thinks-our-consciousness-originates-at-the-quantum-level" target="_blank">check out his views</a> on the quantum-level origins of our consciousness.</p>
Roger Penrose - Did the Universe Begin?
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Scientists identify 24 planets potentially better suited for life than Earth
The study identified superhabitable planets outside of our solar system.
07 October, 2020
Credit: sdecoret on Adobe Stock
- The odds are that if Earth had the right conditions for the development of life, other places probably do, too.
- Scientists have identified two dozen planets that match some items on the list of desirable traits.
- All of these planets are too far away to reach with current tech, but may be valuable research targets.
<p>It's called the "<a href="https://bigthink.com/experts-corner/seeing-earth-from-space-how-true-awe-changes-you" target="_self">overview effect</a>." You know, the renewed appreciation and protectiveness that astronauts orbiting the globe come to feel looking down on our precious Earth. The sense of profound awe and gratitude that we find ourselves in a place so special among the cold, vast emptiness of space. Now a study from Washington State University (WSU) says there are lots of planets out there better than this one.</p>
Superhabitable
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ3MzYwNC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxMjYwOTE5NX0.7WH5907n-K3Ew9QP96D1ohm_yUDEcwH_XjnDwnICYQM/img.jpg?width=980" id="206f9" class="rm-shortcode" data-rm-shortcode-id="ef375f57087011a2324d7f086e3b96c1" data-rm-shortcode-name="rebelmouse-image" />The 24 candidates in their habitable zone near K dwarf stars
Credit: Schulze-Makuch, et al./Astrobiology
<p>On the other hand, all that desirable real estate is pretty far away — none of these 24 "superhabitable" planets are less than 100 million light years from Earth. They were identified in a study led by geologist <a href="https://news.wsu.edu/tag/dirk-schulze-makuch/" target="_blank" rel="noopener noreferrer">Dirk Schulze-Makuch</a> of WSU and Technical University in Berlin, Germany. He was joined in the research by astrophysicists <a href="https://www2.mps.mpg.de/homes/heller/" target="_blank">René Heller</a> of the Max Planck Institute for Solar System Research in Germany and <a href="https://www1.villanova.edu/villanova/artsci/astronomy/meet_us.html?mail=edward.guinan@villanova.edu&xsl=bio_long" target="_blank">Edward Guinan</a> of Villanova University.</p><p>The open-access study is published in the journal <a href="https://www.liebertpub.com/doi/10.1089/ast.2019.2161" target="_blank">Astrobiology</a>.</p><p>Ignoring the possibility that other planets might be even more likely to support life than ours is, after all, like someone insisting they live in the best country in the world without having visited any others. The study puts it this way: "Neglecting this possible class of 'superhabitable' planets, however, could be considered anthropocentric and geocentric biases."</p><p>In searching for superhabitable planets among the 4,500 known candidates, the scientists were not so much looking for somewhere for us to escape to as they were spotting planets that were most likely to be populated by intelligent life. Their hope is to offer up interesting targets for future investigation by instruments such as the European Space Agency's <a href="https://sci.esa.int/web/plato" target="_blank" rel="noopener noreferrer">PLATO space telescope</a>, as well as NASA's <a href="https://www.jwst.nasa.gov" target="_blank">James Webb Space Telescope</a> and <a href="https://asd.gsfc.nasa.gov/luvoir/" target="_blank" rel="noopener noreferrer">LUVOIR space observatory</a>.</p><p>Schulze-Makuch tells <a href="https://news.wsu.edu/2020/10/05/planets-may-better-life-earth/" target="_blank">WSU Insider</a>:</p><p style="margin-left: 20px;">"With the next space telescopes coming up, we will get more information, so it is important to select some targets. We have to focus on certain planets that have the most promising conditions for complex life. However, we have to be careful to not get stuck looking for a second Earth because there could be planets that might be more suitable for life than ours."</p><p>Before one can go searching for superhabitable planets, once must figure out what that word means.</p>Blame it on the sun
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ3MzYxNC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2NjAwNDUyNn0.bv9FioVLoHPE7IxjWnmRzfNKkeGI6UOioEorxSqMapU/img.jpg?width=980" id="7f28c" class="rm-shortcode" data-rm-shortcode-id="5613866aa3c976f165e51f4565517e90" data-rm-shortcode-name="rebelmouse-image" />Credit: Tungdil Preston/Unsplash
<p>The scientists first had to work out the type of sun a superhabitable planet would be most likely to orbit. Interestingly, they decided against dwarf type G stars — also known as "dG stars" — similar to our own sun. After all, they write, "Since it took about 3.5 billion years on Earth until complex macroscopic life appeared, and about 4 billion years for technologically advanced life (us), life on many planets orbiting dG stars may simply run out of time."</p><p>Another issue is that young dG stars spin 10 times as fast as our mature Sun now does, producing "high levels of magnetic dynamo-driven activity and very intense coronal X-ray and chromospheric FUV emissions, which makes the origin and early evolution of life challenging."</p><p>The study settles on planets orbiting type K stars. These stars are a bit cooler than ours and less luminous, but they live a long time, longer than the Sun, from 20 to 70 billion years. This would give their planets more time to get life going.</p>Size matters
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ3MzYxNy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxNjkxMzg4Nn0.x8YqDvGmdmooMUSRu7oJCGTKiwg5VPrqZaoboVOa5fQ/img.jpg?width=980" id="f48b4" class="rm-shortcode" data-rm-shortcode-id="372b444990b8ca7a2520d3bca8124851" data-rm-shortcode-name="rebelmouse-image" />Credit: AleksandrMorrisovich/Shutterstock
<p>Planets with a greater mass than ours were deemed desirable for a few reasons, so long as they were not so big as to become gas giants and so on. These planets would have robust, thick atmospheres, slightly higher temperatures for nurturing life, and lots of elbow room: "This would have advantages for the distribution of species and settlements of islands and continents."</p>Environmental requirements
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ3MzYyNC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1MjQ4NzM5Mn0.9dDvWvYfJY63wX2QbZ0SnITCtsSAMzAoK0H4pfG7D8Q/img.jpg?width=980" id="d973e" class="rm-shortcode" data-rm-shortcode-id="b2e925bc9949378ce37bbc318ff35493" data-rm-shortcode-name="rebelmouse-image" />Credit: BeeBright/Shutterstock
<p>The researchers also settled on an environmental checklist for superhabitable planets. Based on the conditions that allowed life to form on Earth, a planet would have to have the following life-supporting conditions as explained in the study:</p><ul><li><em>T</em><em>emperatures</em> —"Submarine hydrothermal systems, geothermal hot springs, brine pockets in sea ice at about −30°C, deep continental areas"</li><li><em>pH</em> — "Acid mine drainage, geothermal sulfurous sites (e.g., Yellowstone) Soda lakes, peridotite-hosted hydrothermal systems (e.g., Lost City vent)"</li><li><em>Water activity</em> — "Deep-sea brines, soda lakes, evaporate ponds, dry soils and rocks, food with high solute content"</li><li><em>Lower O2 content </em>— "Anoxic marine or lacustrine sediments, intestinal organs, early Earth environments"</li><li><em>Pressure</em> — "Deep oceanic trenches such as the 11,100 m deep Marianas Trench, Martian surface conditions (based on laboratory experiments)"</li><li><em>Radiation</em> — "No natural source of radiation on Earth at levels tolerated by D. radiodurans"</li><li><em>Chemical extremes</em> — "Submarine hydrothermal vent fluids and sulfides; some high-metal containing lakes"</li></ul>We have some winners. Sort of.
<p>Of the superhabitable candidates the study detected, none totally meet the researchers' criteria, though one has four of them, meaning it may be more likely to have life on it than Earth did, and it might be a place we could consider quite comfy.</p><p>Concludes Schulze-Makuch, "It's sometimes difficult to convey this principle of superhabitable planets because we think we have the best planet. We have a great number of complex and diverse lifeforms, and many that can survive in extreme environments. It is good to have adaptable life, but that doesn't mean that we have the best of everything."</p>
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Scientists find 'smoking gun' proof of a recent supernova near Earth
A supernova exploded near Earth about 2.5 million years ago, possibly causing an extinction event.
06 October, 2020
Credit: NASA/ESA/G. Bacon, STScI
- Researchers from the University of Munich find evidence of a supernova near Earth.
- A star exploded close to our planet about 2.5 million years ago.
- The scientists deduced this by finding unusual concentrations of isotopes, created by a supernova.
<p>If you wanted some more shattering news, we now know that a supernova exploded very close to Earth about 2.5 million years ago. That might sound like a long time ago, but in the life of our 4.5 billion-year-old planet, that's just yesterday.</p><p>Supernovas are amazingly bright explosions of stars at the end of their lives. A <a href="https://www.newscientist.com/article/2240389-astronomers-have-spotted-the-most-powerful-supernova-ever/" target="_blank">recent study</a> found a blast 4.5 million light-years away could release as much as 10 times the amount of energy that a sun can emit in its lifetime. It also spreads a tremendous amount of chemicals all throughout the cosmos. Just-released research looked at such a spread and found that concentrations of particular elements point to a supernova near Earth just 2.5 million years ago. </p><p>The scientists found an unusual amount of 53Mn<strong>, </strong>a radioisotope made by supernovas. Previous studies looked for such traces in concentrations of 60Fe, an isotope of iron. </p>
<p>The scientists, led by Dr. Gunther Korschinek from the Technical University of Munich, focused their study on <a href="https://link.springer.com/referenceworkentry/10.1007%2F978-3-319-39312-4_101" target="_blank">ferromanganese crusts</a>. These marine sediments, composed mainly of iron and manganese oxides, grow in time and jut out from the water. This makes them great record-keepers of chemicals in the water around them. While examining these ferromanganese crusts from locations in the Pacific Ocean, the team found not only the isotope 60Fe, but also 53Mn. The samples came from 1,589 meters (5,213 feet) down to 5,120 meters (3.18 miles) down. </p><p>What does the presence of <strong>60Fe</strong> tell the researchers? It's half-life of 2.6 million years indicates that it was created in a nearby supernova explosion in relatively recently times. Otherwise, 60Fe would have decayed into nickel.</p><p>One other explanation for the presence of the isotope is its possible creation in the death throes of <a href="https://en.wikipedia.org/wiki/Asymptotic_giant_branch" target="_blank">asymptomatic giant branch</a> (AGB) stars. But the presence of 53Mn, which cannot be produced by such stars, clearly points to supernovae as the origin, think the scientists.</p>
<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ3MDg3NS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYwOTA2MTQ3N30.yaf3U5WWhXZm1xjKVY-MTVeLQoPpJx51EHwEsa12i4s/img.jpg?width=980" id="1fd30" class="rm-shortcode" data-rm-shortcode-id="c08d448eecf1b9678383f041df868eae" data-rm-shortcode-name="rebelmouse-image" alt="manganese crust" />
This Manganese crust started to form about 20 million years ago. Growing layer by layer, it resulted in minerals precipitated out of seawater. The presence of elevated concentrations of 60 Fe and 56 Mn in layers from 2.5 million years ago hints at a nearby supernova explosion around that time.
Credit: Dominik Koll/ TUM
<p style="margin-left: 20px;">"The increased concentrations of manganese-53 can be taken as the 'smoking gun' – the ultimate proof that this supernova really did take place," shared Dr. Korschinek in a <a href="https://www.eurekalert.org/pub_releases/2020-09/tuom-sei093020.php" target="_blank">press release.</a></p><p>The researchers used <a href="https://en.wikipedia.org/wiki/Accelerator_mass_spectrometry" target="_blank" rel="noopener noreferrer">accelerator mass spectrometry</a> to locate the 53Mn atoms in the crust that looks like hardened chocolate cake. </p><p>"This is investigative ultra-trace analysis," <a href="https://www.sciencealert.com/a-supernova-exploded-dangerously-close-to-earth-2-5-million-years-ago" target="_blank">said</a> Korschinek. "We are talking about merely a few atoms here." He explained further that the technique is also very useful in figuring out the sizes of the original stars, adding "accelerator mass spectrometry is so sensitive that it even allows us to calculate from our measurements that the star that exploded must have had around 11 to 25 times the size of the sun."</p><p>If there was a supernova in Earth's relatively recent history, what effect did it have on the planet? The scientists think it likely caused cosmic ray showers and affected the climate. It might have also caused a partial extinction event – the <a href="https://www.nature.com/articles/s41559-017-0223-6" target="_blank">Pliocene marine megafauna extinction</a></p><p>Check out the study "<a href="https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.125.031101#fulltext" target="_blank">Supernova-Produced 53Mn on Earth</a>" in the journal Physical Review Letters.</p>
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