Zircons in a Martian meteorite widens the possible timeframe for life on Mars.
- A meteorite from Mars unexpectedly contains zircons that reveal the planets history.
- The rock likely comes from one of the solar system's tallest volcanoes.
- Analyzing the zirconium required smashing some very expensive rock.
Zirconian time capsules<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc5NDYyNi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1NDU1NzI1OH0.URoz_gzrLswB109_j2MJha-A5a_S0wx2n75HlYZ2esk/img.jpg?width=980" id="61509" class="rm-shortcode" data-rm-shortcode-id="c04d2caf50da8a0efdf061be4ca49bf6" data-rm-shortcode-name="rebelmouse-image" />
Earth zircon in gem form atop calcite
Credit: Rob Lavinsky, iRocks.com/Wikimedia<p>"We were quite surprised and excited when we found so many zircons in this Martian meteorite," says Bizzarro. "Zircon are incredible durable crystals that can be dated and preserve information that tell us about their origins." Zircons are a rarity on Mars' surface — which resembles the crust beneath Earth's ocean floors — and so scientists have not been expecting to find much of the mineral.</p><p>What makes this so intriguing, Bizzarro explains to the <a href="https://dg.dk/en/mars-meteorite-black-beauty-expands-time-frame-for-potential-life-on-the-red-planet/" target="_blank" rel="noopener noreferrer"><u>Danish National Research Foundation</u></a>, is that zircon "functions as a small time capsule because it obtains and saves information about the environment as well as when it was created. In this case a time capsule with hafnium, which comes from Mars' early crust, which existed around 100 million years before the oldest zircon in Black Beauty was created. Thus, Mars got an early start in comparison with Earth, whose solid crust was created much later."</p>
Breaking Black Beauty<p>Big Think readers may recall that the meteorite — known as "Black Beauty," though its official name is "Northwest Africa 7533" — cost the university $500,000 dollars for 50 grams of its 319.8-gram volume. As such, deciding to perform any sort of analysis that requires damaging the precious rock is not a decision taken lightly, as when, say, zircons are found in the stone.</p><p>"One of the big challenges," <a href="https://snm.ku.dk/english/news/all_news/2018/2018.6/the-meteorite-black-beauty-expands-the-window-for-when-life-might-have-existed-on-mars/" target="_blank" rel="noopener noreferrer"><u>says</u></a> Bizzarro, "has been that the zircons in Black Beauty are extremely small. This called for a courageous strategy: We crushed our precious meteorite. Or to be precise: We crushed 5 grams."</p><p>The decision paid off, says Bizzarro: "Today, I'm glad we chose that strategy. It released seven zircons, one of which is the oldest known zircon from Mars. And from the zircons and their content of hafnium, we can now conclude that the crystallization of the surface of Mars went extremely fast: already 20 million years after the formation of the solar system, Mars had a solid crust that could potentially could house oceans and perhaps also life."</p><p>Eventually, the team would crush 15 grams of Black Beauty, extracting 60 zircons.</p>
Old and young zircons<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc5NDYzNS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1NjI5MDg3OX0.AJwFBV9m2ygMbq-78hXqwUy359wi_V-VJzV6iHXZ9mk/img.jpg?width=980" id="2feeb" class="rm-shortcode" data-rm-shortcode-id="cdb506ceff0db1132127e2c5aac1ff6a" data-rm-shortcode-name="rebelmouse-image" />
The oldest Martian zircon found so far
Credit: Martin Bizzarro/University of Copenhagen<p>"Zircon is a very solid mineral that is ideal for making such an absolute dating of time. In this regard, zircon can be used as a portal to pinpoint a time frame for the history of crust formation on Mars." Dating of Black Beauty's zircons shed new light on the planet's history. Most of the minerals were dated back to roughly 4.5 billion years ago, the earliest days of the planet.</p><p>Unexpectedly, though, some of the zircons were more recently formed, a period from about 1,500 million years ago to 300 million years. "These young ages were a great surprise," recalls Bizzarro.</p><p>That finding may have to do with where the rock came from. "The Black Beauty meteorite is believed to come from the southern hemisphere of Mars, which does not have any young volcanic terrains. The only possible source for these young zircons is the Tharsis volcanic province located in the northern hemisphere of the planet, which contains large volcanoes that were recently active," Martin Bizzarro adds.</p><p>That province, known as the Tharsis bulge, is a huge volcanic area that's got the largest volcanoes, up to 21 kilometers (13 miles) high, yet seen anywhere in the solar system. It's believed that since Mars lacks plate tectonics, volcanoes gather in a single area, beneath which a massive reservoir of magma is likely located.</p><p>First author of the study is Mafalda Costa , who says, "Having samples of the deep interior of Mars is key. This means that we can now use these zircons to probe the origin of the volatile elements on Mars, including its water, and see how it compares with Earth and other planets in the Solar System."</p><p>The most important element the zircons contain for the purpose of looking into Mars history is hafnium. Bizzarro explains that hafnium "retains a memory of where the zircon formed. We found that the hafnium isotope composition of the young zircons is unlike any of the known Martian meteorites, which indicates that the young zircons come from a primitive reservoir that we did not know existed in the interior of Mars."</p>
A team of astrophysicists used AI to figure out which clusters of stars merged to become our galaxy.
- Scientists use artificial intelligence to reconstruct the globular clusters that merged to form our Milky Way galaxy.
- The researchers ran simulations on a neural network to discover the history and details about our galactic ancestors.
- They found that a collision with a previous galaxy called "Kraken" was so powerful it transformed the Milky Way.
Check out how E-MOSAICS simulations shows the formation of a galaxy like the Milky Way:<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="9501816f4e3f2dea501e300adccb7ab3"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/v-v5bSnDZs8?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span>
Credit: D. Kruijssen / Heidelberg University<p><em>Galaxy merger tree of the Milky Way. The main progenitor of the Milky Way is shown by the trunk of the tree, with color representing its stellar mass. Black lines show the five identified satellites. Grey dotted lines demonstrate other mergers that the Milky Way likely underwent, but could not be connected to a particular progenitor. From left to right, the six images at the top list the identified progenitor galaxies: Sagittarius, Sequoia, Kraken, the Milky Way's Main progenitor, the progenitor of the Helmi streams, and Gaia-Enceladus-Sausage.</em></p>
Using a laboratory model, scientists get a nice Jovian surprise.
Europa<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc3MTI1My9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2NDI3NDc0NX0.JbEiK8PdcXijlCQpx64kRa31ZK7LHYBxWbSNvYDnPtk/img.jpg?width=980" id="82e0a" class="rm-shortcode" data-rm-shortcode-id="9b59f7517b28903965ceda93f5ea2fda" data-rm-shortcode-name="rebelmouse-image" />
Enhanced closeup of the "chaos terrain" that is the icy surface of Europa
Credit: NASA/JPL-Caltech/SETI Institute<p>Europa is believed to have an ocean of water or slush beneath its chaotically-featured water-ice surface. <a href="https://solarsystem.nasa.gov/moons/jupiter-moons/europa/in-depth/" target="_blank">According to NASA</a>, it's suspected that the moon's ice layer is 10 to 15 miles thick and floats atop an ocean 40 to 100 miles deep. Europa is just a quarter the size of Earth, but its vastness and depth may mean that it has twice as much water as all of our oceans combined.</p><p>With water considered to be a prerequisite for life, scientists' interest in Europa is obvious. NASA is sending the radiation-resistant <a href="https://europa.nasa.gov" target="_blank">Europa Clipper</a> there to have a look. The spacecraft will conduct 45 flybys at different distances, ranging from 1,675 miles to 16 miles above the ice. The Europa Clipper will carry cameras, spectrometers, ice-penetrating radar, magnetometer, thermal instruments, a device for measuring gravity, and more.</p><p>NASA has previously detected what may be vapor plumes extending outward from Europa. If the Europa Clipper confirms their existence, it may be possible in the future to sample the moon's escaping vapors without needing to land or drill through the ice.</p>
ICE-HEART<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc3MTI0OS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxMzczOTc0MX0.yHxmPxW2kGnOS781_VJTNQilyM6u42dr16-ySPJqpKU/img.jpg?width=980" id="0a149" class="rm-shortcode" data-rm-shortcode-id="a3a27b24fb13430dd900d92e9267bf38" data-rm-shortcode-name="rebelmouse-image" />
Artist's impression of Europa against a backdrop of Jupiter
Credit: NASA/JPL-Caltech<p>The researchers modeled Europa's response to Jupiter's radiation using a special instrument they constructed called the Ice Chamber for Europa's High-Energy Electron and Radiation Environment Testing (ICE-HEART). To blast it with radiation, they took it to the Medical Industrial Radiation Facility at the National Institute of Standards and Technology in Gaithersburg, Maryland, a high-energy electron beam facility.</p><p>Expecting that Europa's oceans would contain a mix of water and salts similar to those on Earth, they were investigating the response of various materials to radiation. They began with magnesium sulfate and sodium chloride — essentially Epsom salt and table salt — both believed to be in Europa's ice.</p><p>They weren't surprised to see some glowing caused by energetic electrons getting through the moon's ice and energizing molecules beneath it. The glow is generated when the molecules relax after exposure.</p><p>However, the variety of colored glows emitted by radiated compounds was a surprise, according to co-author Bryana Henderson. "We never imagined that we would see what we ended up seeing," Henderson said. "When we tried new ice compositions, the glow looked different. And we all just stared at it for a while and then said, 'This is new, right? This is definitely a different glow?' So we pointed a spectrometer at it, and each type of ice had a different spectrum." (Spectrometers divide light into wavelengths that can signify specific compounds.)</p><p>"Seeing the sodium chloride brine with a significantly lower level of glow was the 'aha' moment that changed the course of the research," said co-author Fred Bateman.</p>
Both sides now<p>We can see our own moon because it reflects sunlight. Most spectrometer readings of Europa have thus far been derived from observations of its light-reflecting bright side.</p><p>"If Europa weren't under this radiation," said Gudipati, "it would look the way our moon looks to us — dark on the shadowed side. But because it's bombarded by the radiation from Jupiter, it glows in the dark."</p><p>This means that the moon's dark side also emits light in the form of its glow, so here come the spectrometers. Gudipati said of the research, "We were able to predict that this nightside ice glow could provide additional information on Europa's surface composition. How that composition varies could give us clues about whether Europa harbors conditions suitable for life."</p><p>He adds, "It's not often that you're in a lab and say, 'We might find this when we get there. Usually, it's the other way around — you go there and find something and try to explain it in the lab. But our prediction goes back to a simple observation, and that's what science is about."</p>
Celebrate Science Day 2020 by proving the Earth is not flat.
- Flat-Earthers drive rational people nuts.
- A physicist offers three experiments to confirm it is those people who are crazy, not you.
- The experiments, however, do require a belief in mathematics.
Experiment 1: Catch a sunset twice<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc2ODQxMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1Mjk0Mzg5NX0.VR2LnQx4TKhyTwmSoZSkDfsOMgqac4d6Drm49vyYCGA/img.jpg?width=980" id="64198" class="rm-shortcode" data-rm-shortcode-id="294982a49a33773d038f756f7227b37d" data-rm-shortcode-name="rebelmouse-image" />
Credit: Johannes Plenio/Unsplash<p>At the top of the calculator is the "Select an experiment" drop-down menu. Let's start with the "<a href="https://www.omnicalculator.com/physics/flat-vs-round-earth#sunset-twice-experiment" target="_blank">sunset twice</a>" experiment.</p><p>Wooding notes that you can prove the Earth is round by standing up quickly right after the Sun goes down and getting ahead of the shadow cast by the horizon so you can see the sun set a second time. If the planet were flat, once it went over the edge from your first viewing position it would be gone.</p><p>You may want to find out the time of sunset before testing out the calculator. There are many places online to find this information. <a href="https://www.timeanddate.com/sun/" target="_blank">Here's one</a>.</p><p>To use the calculator, begin by selecting a city in your time zone. Wooding has pre-entered the sunset duration for you, though you can look up the precise value online for your location.</p><p>There are three ways to increase your height, selected from the "Ideas" menu: standing up from a lying down position, taking the sky-lift elevator at the <a href="https://en.wikipedia.org/wiki/Burj_Khalifa" target="_blank" rel="noopener noreferrer">Burj Khalifa Hotel</a> in Dubai, or sending up a drone with a camera on it. Most of us will select the first option.</p><p>Next, you enter your starting height (the default for lying down is .6562 feet), how long it will take you to stand up, and then the final standing elevation, presumably of your eyes.</p><p>What the calculator finds for you is the percentage of the second sunset you'll see. Note that for the sky-lift and drone tests, you see a lot more of that second sunset given the greater height and your accelerated ascent speed.</p>
Experiment 2: Disappearing object<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc2ODQxMy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0MDIzOTU5MX0.NUrgcREKhtrD4TfGtDTDB7_WuCbYTreoXSTnWCsE3Mw/img.jpg?width=980" id="fdac5" class="rm-shortcode" data-rm-shortcode-id="d6fd8797e0bffb64f96d6104e04d09c4" data-rm-shortcode-name="rebelmouse-image" />
Credit: Michael Olsen/Unsplash<p>Thanks to the curvature of the Earth, you can make an object on a distant lake shore seem to <a href="https://www.omnicalculator.com/physics/flat-vs-round-earth#disappearing-object-experiment" target="_blank">disappear</a> with a change in viewing height.</p><p>You'll need binoculars for this one. And, um, a lake.</p><p>The calculator will tell you how much of the object will become unobservable after you fill in the three values.</p><p>(You may also need a boat to measure the distance.)</p>
Experiment 3: Stick shadows<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc2ODQyMS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0NTM2MTg0Nn0.eyqFl7ulLoMf8UvNYXoPrZ3vcLwyygaM9QJ70EjD9NI/img.jpg?width=980" id="3d767" class="rm-shortcode" data-rm-shortcode-id="2ba382e4212a5f7a8ad4e58dba4e38b1" data-rm-shortcode-name="rebelmouse-image" />
Credit: Logan Radinovich/Unsplash<p><a href="https://www.omnicalculator.com/physics/flat-vs-round-earth#instructions-for-measuring-how-big-the-earth-is-using-stick-shadows" target="_blank">For this one</a> you'll need a cooperative friend who lives at least some distance away, or a teleporter. Also two sticks and a day with enough sunlight to cast shadows in both locations.</p><p>This experiment involves measuring shadows cast at two different locations and calculating the angle between them to arrive at the Earth's circumference.</p><p>This experiment is a little advanced mathematically, and Wooding offers a help link if you're confused.</p>
A new study from NASA and the SETI Institute comes up with an exciting number of potentially life-supporting planets.
- A study analyzes data from the Kepler Space Telescope and the European Space Agency's GAIA survey to estimate the number of habitable planets.
- There may be 30 such planets in our own galactic neighborhood.
- The new estimate may help inform future research and missions.
What the study finds<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDY3NTYwNi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxNTU3Nzg1N30.swHaJYjq0p2WFJaUltnkFj9_6CVCP0oEQ1OBattKiLE/img.jpg?width=980" id="b7242" class="rm-shortcode" data-rm-shortcode-id="33603a8e42b17757ea7983c636c8805c" data-rm-shortcode-name="rebelmouse-image" />
Illustration of Kepler-7
Credit: SETI<p>The team that produced the new report was led by Steve Bryson of NASA's Ames Research Center in California. The authors of the study looked for stars that are similar in size, age, and temperature to our Sun, between 4,527 to 6,027 °C. These stars are <a href="https://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml" target="_blank">either</a> G dwarfs, or slightly smaller and more plentiful K dwarfs. Next, they looked for planets orbiting such stars that ranged in size from 0.5 to 1.5 times the size of Earth on the assumption that they were most likely to be rocky planets like ours.</p><p>A big factor affecting habitability is the ability to support surface water. Earlier estimates of habitable planets have focused primarily on an exoplanet's distance from its sun, the so-called "habitable zone." The new research also takes into consideration the amount of light the planet receives from its sun as a factor in the likelihood of water. The authors of the study supplemented the Kepler data with spectroscopic measurements from the European Space Agency's <a href="https://www.gaia-eso.eu" target="_blank">GAIA</a> survey of a billion stars in the Milky Way.</p><p>The stars can be dim enough that their habitable zones are close, causing any exoplanets there to be tidally locked, which means the same side always faces their sun. This makes the stripping off of their atmospheres more likely. One of the unknowns is the degree to which a planet's atmosphere impacts its ability to retain water, though, and for the current research, the authors presumed that atmosphere has a minimal effect on the likelihood of surface water.</p><p>Taking all this into consideration, the research "estimate with 95% confidence that, on average, the nearest HZ planet around G and K dwarfs is ∼6 pc away, and there are ∼ 4 HZ rocky planets around G and K dwarfs within 10 pc of the Sun." (pc is the abbreviation for <a href="https://en.wikipedia.org/wiki/Parsec" target="_blank" rel="noopener noreferrer">parsec</a>.)</p><p>The study offers both a conservative estimate of the number of habitable exoplanets orbiting their stars — 0.37 to 0.60 planets per star — and a more optimistic one: 0.58 to 0.88 per star. More than half of galaxy's suitable stars may have habitable planets.</p>