Martian Gullies and Inside-Out Planets: Discoveries from the Cosmos

This is Spacetime Series twenty nine, episode twenty five, for broadcast on the twenty seventh of February twenty twenty six. Coming up on space Time, mysterious gullies on the red planet Mars that appeared to have been dug, the discovery of a unique inside out planetary system, and Europe's most powerful rocket undertakes its first launch. All that and more coming up on space Time. Welcome to space Time with Stuart Gary. Scientists have been studying a set of mysterious gullies on the red planet Mars that appear to have been excavated, raising questions of how now. A reporting the journal Geophysical Research Letters as determined the likely corporates aren't Martians, but rather block of frozen carbon dioxide the Steadies. Lead author Roneki Rolos from Utrek University says her tests showed how these blocks of CO two ice were able to dig gullies in a unique way. She says she felt like she was watching the sandworms in the movie June Now. Other researchers had previously suspected that these blocks could play a role in the formation of the gullies, but this is the first work to actually prove it. It's a phenomenon not seen on Earth, and it's never been observed by anyone previously. It works like this. Ice forms in the Martian Southern Hemisphere desert tunes during the winter. That's when temperatures can drop to minus one hundred and twenty degrees celsius. At this time, a layer of co two ice forms over the entire surface of the june field, sometimes up to seventy centimeters thick. Then, at the end of winter, the June slopes heat up and blocks of ice break off, some of which up to a meet along. Now, due to the thin Martian atmosphere and the large temperature differences between the warm June sand and the ice, the bottom of the ice immediately turns into a gas, a process called sublimation. Now, as a kilo of gas requires more space than the same way of ice, the gas pressure blasts away the sand around the block, causing the block itself to dig into the slope. It becomes trapped in a hollow surrounded by small ridges of settled sand. However, the sublimation process continues, and so the sand keeps on being plastered away in all directions. As a result, the block gradually moves downhill, leaving a long, deep gully behind it, with small sand ridges on either side. Once the block reaches the bottom of the slope and stops smoothing, the ice continues to supplimate until eventually all the seat is evaporated, and so all that remains is a hollow in the sand at the bottom of the dune. This space time still to come discoveries of a unique inside out planetary system, and Europe launches its most powerful ever rocket for the first time. All that and more still to cart on space time, Astronomers have discovered a distant planetary system that's turned scientists understanding of planetary formation inside out. Our Sun's planetary system consists of four inner terrestrial rocky worlds Mercury, Venus, Earth, and Mars, followed by the gas giants Jupiter, Satin. You're in a so neptune, but this newly observed system, cataloged as LHS nineteen oh three, is inside out, with a distant, small rocky planet orbiting outside of two gas giants. Now, a fourth planet in the system does all bit closer to the hearst Star than the big gas worlds, but it's still all very strange. The star LHS nineteen oh three is a special type M red dwarf located about one hundred and sixteen light years away. Traditional planetary system models based on our own Solar system obviously suggest that the closest planets to their host stars are rocky worlds because still a radiation sweeps away their gases atmospheres, leaving behind just dense rocky cores. As for the gas giants, they form further out in the cooler regions where gas can accumulate and so planets there can hold on to their extended atmospheres. Yet, the new findings were reported in the journal Science show this distant rocky world orbiting LHS nineteen o three, which appears to have either lost its gases atmosphere or never formed one in the first place. Astronomers made their discovery in data from ESA's KEIOPS characterizing Exoplanets satellite. The studies lead author Thomas Wilson from the University of Warwick says this strange object makes it a unique inside out system. Rocky planets usually don't form far away from the home star beyond the gas giants, so Wilson and colleagues have set out to explore various possible explanations for how this robe rocky planet could have formed. Could the rocky planet have simply been flung out there through gravitational perturbations, or did it lose its atmosphere in some cataclysmic collision. After careful consideration, the authors eventually ruled out both these hypotheses. Instead, they found evidence that these four planets didn't all form at the same time as one would expect, but formed one after the other in a process called inside out planetary formation. If LHS nineteen oh three gave birth to its four planets one after the other, from the inner to the outermost planet, then each planet evolves in turn, swooping up nearby gas and dust and leaving further out planets to wait and potentially evolve in a different environment. Wilson says this means that by the time the final outer planet formed, the system may simply have already run out of gas, which is considered vital for planetary formation. Yet here it is a small, rocky world, defying explanations. He says, it seems that we've found the first evidence of a planet that's formed in a gas deplated environment. So this small rocky outer planet simply be an odd exception, or it may be the first clue of a new pattern of how planetary systems can evolve. Either way, it's a discovery begging for an explanation that lies beyond sciences typical understanding of planetary formation. This is space Time. Still to com Europe's most powerful rocket undertakes its first launch, and the March Equinox, the constellations of tourists, The Bull and Leo, the Lion, and three point one four one five nine Pie Day are among the highlights of the March Night skies on SkyWatch. 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So why not try it for free at squarespace dot com slash space time and when you're ready to launch, use the offer code space time to save ten percent of your first purchase of a website or domain that squarespace dot com slash space time and the promo code space time and remember you'll find the links in our show notes. Arion Space is undertaking the inaugural launch of the new Arian sixty four, Europe's most powerful ever rocket. Mission VA two sixty seven from the European Space Agency's Spaceport in Front carried thirty two satellites into orbit for the Amazon Leo network, which aims to eventually rival Elon Musk Starlink. It's the largest number of satellites ever carried by an Ariane rocket and it carries such a massive load. The Arian six was fitted with four strap on solid rocket boosters rather than the two used on the six previous flights of the new launch vehicle. Amazon now has one hundred and seventy five broadband satellites in orbit, with plans to eventually expand the constellation to some three thousand, two hundred now rival Starlink already has nine four hundred satellites orbiting the planet. After its initial launch in twenty twenty four, the new Arian six rocket undertook five flights last year. Arian Space and the European Space Agency eventually planned to have Arian six undertake an average of ten launches a year. This is space time, and time that'd turn our eyes to the skies and check out the celestial sphere for March on SkyWatch. Happy New Year, Well it would be if this was ancient Mesopotamia or Rome. That's because March was the first month of the new year. Going back to the earliest concept of celebrating New Year's Day at the time of the vernal equinox around two thousand BCE. See the ancient Roman calendar, which had just ten months, designated March first as the new year. That ten month calendar is still reflected today, with the name September or septemb being Latin for seven October Octo, meaning eight November and November nine and December of DECI meaning ten who wasn't really until the Gregorian calendar that January first mark the start of the new year, But in the beginning it was mostly Catholic countries that adopted it. Protestant nations only gradually moved across, with the British, for examp, not adopting the reformed calendar until seventeen fifty two. Prior to that date, the British Empire and its American colonies still celebrated New Year's Day on March twenty fifth. The heart of the month is the March equinox, which will take place at one forty six in the morning of Saturday March the twenty first Australian Eastern daylight time. That's ten forty six in the morning of Friday, March the twentieth the US Eastern daylight time, and two forty six in the afternoon Greenwich meantime. For our listeners in the northern Hemisphere, it means the vernal equinox, the start of spring, although south of the equator it's the autumnel equinox, meaning a move into autumn. The day marks the point in orbit around the Sun when the planet's rotational axis means the Sun will appear to rise exactly due east and set exactly due west to someone standing on the equator, it means almost equal hours of darkness and light. In fact, the very word equinox is derived from the Latin meaning qwie or equal, and knox meaning night. It all comes about because Earth's rotational axis is tilted at an angle of around twenty three point four degrees in relation to the ecliptic, the plane created by Earth's orbit around the Sun. That axial tilt is always pointed at the same position in the sky, regardless of Earth's orbit position around the Sun, so on any other day of the year, either the northern or southern hemisphere it tilted more towards the Sun, But on the two equinoxes, usually around March twenty first and September twenty thirty each year, the tilt of Earth's axis is directly perpendicular to the Sun's rays. However, there's a complication called procession. This causes Earth's spin axis to wobble ever so slightly, just like the axle of a spinning top. The rate of procession is only about half a degree per century. So people don't notice it on human timescales. And because the direction of Earth's axis of rotation determines at which point in Earth's orbit the seasons occur, precession will cause a particular season, for example, the southern Hemisphere autumn to occur at a slightly different place from year to year over a twenty one thousand year cycle. At the same time, Earth's orbit itself is subjected to small changes called perturbations see Earth's orbits and the lips, and there's a slow change in its orientation which gradually shifts the point of perihelion, Earth's closest dobital position to the Sun. Now, these two effects, the procession of the axis of rotation and the change in the orbit's orientation, work together to shift the seasons with respect to perihelion. And because we use a calendar year that's aligned to the occurrence of the seasons, the date of perihelion gradually regresses through a twenty one thousand year cycle. And there's another complication. Australia and some of the other Commonwealth countries start their seasons on the first day of the month, what are referred to as meteorological seasons. Rather than on the solstice season equinoxes, which are referred to as astronomical seasons, so that means Australia's autumn officially began on March first, rather than on the day of the March equinox. Meteorological seasons are used because it makes it easier for meteorologists and climatologists to break the seasons down into more exact three month calendar groupings for comparing seasonal and monthly statistics. The moment of the March equinox is also important in astronomy because it's used to define the celestial coordinate system of right ascension and declination. In astronomy, the celestial coordinate system is the astronomical equivalent to the latitude and longitudinal coordinates used on Earth's surface. It's used to specify the position of objects in three dimensional space and the direction of those objects on the celestial sphere, the imaginary globe surrounding the Earth. In other words, it lets scientists determine the position of a celestial object such as a satellite, are planet, stars, galaxies, and so on. Right ascension, which uses the symbol alpha, is the angular distance measure eastwards along the celestial equator from the vernal equinox on the celestial sphere. Its analogous to terrestrial longitude declination, which uses the symbol delta measures the angle north or south of the celestial equator, and so it's the celestial equivalent to terrestrial latitude markie. The vernal equinoxen setting in the western evening sky this time of year is one of the oldest recognized constellations in the heavens. Taurus the Bull, so named around six thousand years ago in Greek mythology, Taurus represents the king of the god Zeus. Zeus lasted after King Ajino's daughter Europa, who was looking after a herd of cattle. Now, being a god and with god like powers, Zeus decided to transform himself into a powerful white ball so that he could get closer to the beautiful Europa. Now once transformed into a ball, Zeus convinced Europe to climb on his back, and he then carried her off to the island of Crete. Taurus has said is represented by a dominant V shaped grouping of stars. The bright ready star in the group is Aldebaran, an orange giant one and a half times the mass of the Sun, located sixty. Five light years away. A light year is about ten trillion kilometers, the distance of Perdon can travel in a year at three hundred thousand kilometers per second, the speed of light in a vacuum, and the ultimate speed limit of the universe. Alibran is the fourteenth brightest star in the night sky and the closest bright star at the point of the vernal equinox. In ancient Arabic, Order Bran's name means the follower, as it appears to follow the seven sisters of the Plates. It's also the first of the four royal or guardian stars identified by the ancient Mesopotamians. Now, that v shaped grouping of stars knee Alibaran is known as the Hyades. It's the nearest young open star cluster to Earth, Located just one hundred and fifty three light years away. Between Orderbran and the Orian constellation, you'll see a bright red star that's Bettlegoes, the ninth brightest star in the night sky these days, more commonly called Beetlejuice. If you turn to the. North now, you'll see the two bright stars Pollux and Casta, which represent the northern constellation. Of Gemini, the twins. In Greek mythology, they were brothers who traveled with Jason aboard the ship Argo in search of the Golden Fleece. Poul Axe is an orange hued evolved giant star located thirty four light years away. It has about twice the Sun's mass and has bloated out to around eleven times the Sun's diameter. In two thousand and six, an extra solar planet or exoplanet, designated Polax B was discovered orbiting the star. The planet is a gas giant, orbiting its host star every one point sixty one earth years. The other star, Casta, is located some fifty one light years away, and it's actually a system of six stars comprising three eclipsing binaries. Eclipsing binaries the binary star systems, in which the orbital plane of the two stars and the system lies so nearly along the line of sight from the observer here on Earth that the stars appear to eclipse each other. Looking to the northeast now, and you'll see the star Regulus or Little King, the brightest star. The constellation Leo. The Lion is mentioned by Homer in his famous eighth century BCE polm the Odyssey. According to Greek mythology, Leo was killed by Hercules as the first of his twelve labors. Located some seventy nine light years away, Regulus is a modible star system composed of at least four stars. Regulus, a designated Alpha Liernus, is a spectroscopic binary comprising a rapidly spinning spectral type B blue white star around three and a half times more massive than the Sun with some two hundred and eighty eight times the Sun's luminosity, and a small companion star, most likely a white dwarf. There's still a corpse of what once would have been a Sun like star. The pair take about forty days to orbit each other. Spectroscopic binaries a double star systems orbiting each other so closely and at such an angle that they can only be visually separated from our viewpoint here on Earth, at least by their spectroscopic signatures. Astronomers describe stars in terms of spectral types. It's a classification system based on ten which are and characteristics. The hottest, most massive, and most luminous stars are known as spectual type O blue stars. They're followed by spectual type B blue white stars, then specual type A white stars, spectual type F whitish yellow stars, then spectual type G yellow stars. That's where our sun fits in. Then there's spectual type K orange stars, and the coolest and least massive of all stars are specual type M red stars, commonly referred to as red dwarfs. Each specual classification system is further subdivided using a numeric digit to represent temperature, with zero being the hottest and nine the coolest, and then you add a Roman numeral to represent luminosity. So our Sun technically is a G two val G two five. Yellow dwarf star. Also included in the stellar classification system are special types LT and Y, which are assigned to feldstars known as brown dwarves, some of which were born as specual type M red dwarf stars but became brown dwarfs after losing some of their mass. Brown dwarves fit into a unique category between the largest planets, which can have around thirteen times the mass of Jupiter, and the smallest spectual type M red dwarf stars, which are around seventy five to eighty times the mass of Jupiter or about zero point zero eight solar masses. The primary star in now for the earnest, completes a full rotation around its axis in under sixteen hours. That's incredibly quick, especially when compared to our Sun's thirty day rotational period. Now this gives the primary star an oblate appearance, and it causes what's known as gravity darkening, meaning its poles are considerably hotter and five times brighter per unit surface area than its equatorial region. Scientists estimate that if it were rotating just fifteen percent faster, the star's gravity would be insufficient to hold it together and it would literally spin itself apart. Located further away at Regulus BCND, which are all dim main sequence stars. Main Sequence stars are those undergo showing hydrogen fusion into heal him in their core, like the Sun's currently doing. Regulus B and C are thought to orbit each other every six hundred earth years and are located around five thousand astronomical units away from Regular SA. An astronomical unit is the average distance between the Earth and the Sun, around one hundred and fifty million kilometers or eight point three light minutes. Regular SP is a spectrol type F white yellow star, while its companion Regular C is a small spectral type M red dwarf star. Regulus D is a bit more of a question mark. It's a dim star, and at least from our point of view, it appears to be sharing motion across the sky with. Other members in the group. At the opposite end of the constellation of Regulus is the star Beatterleerness or Dinebola, the Horse's Tail. It's a luminous white star thought to be spectual type A, about half as bright as Regulus and the third brightest star in the constellation Leo. Bitter Leona says about one point eight times the mass of the Sun and about fifteen times the Sun's luminosity. It's suspected of being a dwarf cepide or Deeta scuty type variable star, meaning its luminosity varies very slightly over a period of several hours due to pulsations on its surface. Also at the other end of Leo other stars theater and loterlyoners the loins of the lion. Theaterlyess is about one hundred and sixty five light years away. It's a very young spectrotype a white star about two and a half times the mass of the Sun, with an age of just five hundred and fifty million years. Theatreally eerness a spectra shows enhanced absorption lines for metals, that is, elements other than hydrogen and helium. This increased metallicity appears around twelve percent higher than the Sun, allowing the star to radiate with some one hundred and forty one times the luminosity of the Sun from its outer atmosphere at an effective temperature of nine thy three hundred and fifty keelven, literally giving it a white hot glow. Located some seventy nine light years away, lotally Onness is another spectroscopic binary consisting of two stars orbiting each other every one one hundred and eighty three earth years. The primary star is a spectrotype F yellow dwarf star, a little hotter. And more massive than the Sun. Algebra or gammily Ernest is a binary star system with a visible third component. The two primary stars are located one hundred and twenty six light years away and can be resolved in a backyard telescope. Both are yellow giants, orbiting each other every six hundred earth days. The unrelated tertiary star named fortyle Earns is a yellow tin star which can be seen through binoculars. Its traditional name Algebra, means the forehead. Other stars in the system include Diltterleerness or Zosma, which is a blue white star fifty eight light years from Earth, Epsilonly Earnest, a yellow giants some two hundred and fifty one light years from Earth, and Zeally Earnes and optical triple Star. The brightest component is a white giant about two hundred and sixty light years from Earth, while the second brighter star, thirty nine Earnest, is widely spaced and is located to the south of the primary, with the third and faintest star in the system, thirty five Lye, located to the north. Also located in Leo is Taulenus, visible as a double star through binoculars. It includes a yellow giant located some six hundred and twenty one light years from Earth, and a binary secondary star fifty four Learners, a pair of blue white stars, the visible in small telescopes and located two hundred and eighty nine light years from Earth. Also in the constellation Leo, you'll find the Leo triplet, a group of three galaxies Messia sixty five, Messia sixty six, and NNGC thirty six twenty eight, all appearing relatively close together. Messia sixty five, also known as MNGC thirty six twenty three, is an intermediate spiral, possibly barred spiral galaxy about thirty seven million light years away. M sixty five disc appears to be slightly warped, and a relatively recent burst of star formation is suggestive for some gravitational interaction with the other two galaxies in the Leo triplet, possibly around eight hundred million years ago. Nearby is MESSI sixty six NNGC thirty six twenty seven, another intermediate spiral galaxy some ninety five thousand light years wide and about thirty six million light years away. Gravitational interaction from its passing carters with the neighboring galaxies in the triplet has resulted in extremely high central mass concentration, a high molecular to atomic mass ratio, and a resolved, non rotating clump of neutral atomic hydrogen apparently removed from one of its spiral arms. The third member in the group is NGC thirty six twenty eight. The Hamburger Galaxy, a spiral galaxy with a spectacular three hundred thousand light year long tidal trail of gas and stars. MGC thirty six twenty eight is located thirty five million light years away. Its most conspicuous feature is the broad and obscuring band of dust located along the outer edge of its spiral arms, effectively transsecting the galaxy to the view from Earth. Other bright, well known galaxies in LEO include Messia ninety five, Messia ninety six, mess one hundred and five, and NGC twenty nine oh three. M ninety five and M ninety six are both spiral galaxies, each about twenty million light years from Earth. M ninety five is a bad spiral. Another bad spiral galaxy is NNGC twenty nine oh three, which is thought to be very similar in size and structure to our own Milky Way galaxy. It was discovered by William Herschel in seventeen eighty four. Close to the M ninety five M ninety six pair is the elliptical galaxy M one oh five, which is also around twenty million light years from Earth. Okay, let's turn to the east now and the constellation of Corvus the crow in Greek mythology. Corvs was a really clever crow. In fact, he could talk to people. However, after refusing to speak to the god Apollo, he was banished to the sky together with Creter the carpet Hydra the snake. One of the brightest stars in Hydra is al Fad, the solitary one, so named because it appear is all alone in the sky. Okay, turning to the western horizon now, and you'll see the star Akina in the southern tip of the constellation Eridanus. The river Eridanus is one of the largest and longest constellations in the sky. Akina means the river's end, as it marks the end of the River Eridanus, located around one hundred and thirty nine light years away. Akina is a binary star system comprising two stars, Alpha Ridney A and Alpha Rhydney B, one of the ten apparent brightest stars in the night sky. Alpha Orridney A is a young, hot spectual type B blue star about six point seven times the mass of the Sun with a stunning three one hundred and fifty times the Sun's luminosity. Akina is extremely high rotational velocity of over sixteen kilometres per second gives it an oblate shape, making it one of the least veherical stars in the Milky Way, with an equatorial diameter some fifty six percent greater than its polar diameter. This distorted shape means the star displays significant latitudinal temperature variations, its polar temperature being above twenty thousand kelvin, while its equatorial temperature, being much further away from the stollar core, is only around ten thousand kelvin. Those high polar temperatures are generating a fast polar wind, ejecting matter from the star and generating a polar envelope of hot gas and plasma. The companion star Alfur Ridney B appears to be a spectro type, a white star with about twice the mass of the Sun. The two stars orbit each other at an average distance of roughly twelve point three astronomical units. Now, just a quick reminder that March fourteenth marks the yearly celebration of the mathematical constant pi. Pi is the ratio of a circle's circumference to its diameter, but it's also an irrational number, meaning its decimal representation never ends and never repeats more than just a number. Pi has important applications in astrophysics. Orbital mechanics and other fields of astronomy. It's been calculated to over a trillion digits, and the record for a sighting part from memory is over seventy thousand digits. Imagine sitting next to that person at a dinner party. As for me three point one four one five nines about it, of course, as well as pie day. March fourteen is also the birthday of the great professor doctor Albert Einstein. And joining us now for the risk of our tour of the March night skies. You're seeing your science writer and Sky and Telescot Magazine contributor Jonathan Nally. Today, Stuart Yet March night Sky. Now, we normally start our tour of the night sky by looking to the shout, but this time I thought we'd start with the new to the north, at least as we see it from down here where I live within the mid mid latitudes of the Southern Hemisphere. So as I look to the north during March evenings, low down in the northern sky, we've got four constellations of the zodiac. We've got Taurus, Gemini, Cancer and Leo. Famous constellations Cancer and Leo. They're a bit bare for the Naked Eye star games, there's not a lot to see. But Gemini and Taurus, these ones are really really good, great constellations primarily because they've got a couple of really really good while his Taurus had a couple of really really good the starclofters in it. So in Taurus you've got one called the Hyades, which is a V shape or wedge shaped group is stars quite large, it's really quite noticeable. It stands out. And there's another one that's a little way away and it's smaller though quite stunning. It's called the Pleiades all the Seven Sisters, which we've spoken about many many times on the program. That's when I first mentioned the Hyades cluster. It has a fairly bright reddish, really dark reddish sort of star at its head, and that's the star called al Deboron or Aldi Barron or some people call it. That's in Taurus. In Gemini. Gemini also does have some nice star clusters, but you really need a para monoculars to get a good view of those at least and a telescopeia and better. But you can always tell the constellation Gemini because it has two bright stars quite close together and they're both pretty much the same brightness as well. One's called Castor and one is called Pollux, which is two bright stars close to get a similar brightness. Obviously Gemini the twins. So still in the north for us in the southern hemisphere, at least the higher up than those Zodier constellations, we've got the mighty Orion, which is one of the best knownab all the constellations. Of course, we talk about it all the time on the show. Grab the chance to see now during March, because a couple of months time it will have dropped below the western horizon and we won't see it again until the end of the year. This is the thing with constellations this season because for us at this time of year, when it's nighttime, we're looking in one particular direction in space, out into space. Right six months from now we'll be around on the other side of the sun and the night time there will be looking in the opposite direction out into space. So as months go by, constellations drop over the western horizon, they come up in the east, and they just go this repeating pattern every year, every year. Every year, so Orion and the sort of ones crowd the chance to see. And now before the weather we're heading into winter down here in the South, so before the weather gets bad and then we get lots of cloudy weather and you can't see anything. So yeah, another words, to look at it now, because it's going to be going a couple months time now high overhead for us in the South. At least we've got the two brighter stars in the night sky. We've got Serious and Canopus. Serious is actually a binary star system made up of two stars, one a really bright one and the other one you can't see. So the larger of its two stars is about twice as massive as the sun, very bright, and the other one is a very tiny, unseen white dwarf star. You've got no over seeing it. It's really small, very close to its primary star, and just gets drowned out by the light of the main star in Serious. Now, Serious is about twice as bright as Canopus as we see them in the night sky, even though Canopus itself, the second brightest star in the night sky, is four times as massive as Serious, and intrinsically it's much much and brighter. It's a brighter star, but it seems dinner because it's a lot further away. Canopus is three hundred and ten light years from Earth, where Serious is very nearby, it only about eight and a half light years. So if you put Sirius at the same distance as Canopus, it'd be it'll be a nothing sort of star, and Canopus would be the brightest. So this is the thing you need to sort of remember when you're looking up there in the night sky and see all these dark and some are bright and some are dim. Some are bright because they are intrinsically bright, but sometimes it's just because they're close. And stars that are dim may be actually really bright stars, but they're just a long way away. That's the way things go. Now, sweeping south along the way past Serious and format has become to the far southern constellations. That does the shoven Cross or Crux or Crooks, so I'm told it should be properly pronounced in Latin. And another one called Karna, which is a really great constellation to see down there, lots of great stuff to see whether pair of binoculars. The Southern Cross is hard to see at the beginning of the year, of the end of the year. In the beginning of the year, but by by March it's actually quite easy to see. As the months go on and the Earth is rotating. The Southern Cross, which during the end of the year period is way down on the southern horizon and is often below the horizon for many stargazers. It's now up a bit higher, so you should be able to see it no matter what. Just remember that this time of year it's on its left hand side, sort of kite shape, right, So imagine a kite lying on its left hand side and probably about a further way up from the horizon. That's in the mid evening at least. Now, if you're up past midnight, then the Earth will have turned a bit more and therefore the Southern Cross full and risen the higher in the start, and you'll see it standing much higher and standing straight up, which is the way most people imagine it to be. Now, it's God of the planets what we've got. As the evening falls, as there's the darkness starts to fall. This month, only two of the planets visible to naked eye are up and visible, and one of them won't be visible for very long, and that one is Saturn. In the first week of the month, you might just be able to see it as a pin prick of light in the twilight glow out of the west after the sun has set. It will be in the orange blow of sunset after the sun has gone down, but by about the second week of March it will be lost in the Sun's glare. It's going to be around the other side of the Sun and we won't see it for a while. On the other hand, perfectly visible is Jupiter, the biggest planet in the Solar System, and you'll see this one about halfway up from the northern horizon for those where I live in mid latitudes in southern hemisphere, or it'll be to the south, directly to the south if you live in a country north of the equator. Now, Jupiter is pretty hard to miss because, apart from the Moon, it's the brightest thing in the late evening spy at this time of the year. Now I specify late evening sky because there is a third planet that's about to make its appearance, the one that's even brighter than Jupiter, and that's Venus. I mentioned Saturn before, and that it's going to be visible in the first week or so. The tiny pin prick of light in the western twilight glow, while as it disappears, Venus will appear up above the horizon in the west in that sort of glowing orange twilight, and it'll poka set up and it's spasically stay there hugging the horizon for all the rest of the month. So you should be able to see it because Venus is really big and bright, So even though it's in the glare, if you like of the twilight glow, because it's so big and right, you should be able to see it. Now, switching to the hours before sunrise, if you're up early or you're very very late, if you take a look into the dawn blow this time, before the sun peeps up over the horizon, you should see what looks like a small reddish star. Well, that's the planet Mars. And just like Venus, Mars is going to hug the eastern horizon before sunrise for the rest of this month, so you should be able to hear it roughly the same what astronomer is called altitude, but the distance above the horizon for most of the month. Now, if you keep watch, if you're up early at six o'clock or whatever early and you're watching the before the sun rise in the second half of the month, you'll see the planet Mercury. Day by day. It'll just see higher and higher and higher in the sky and it will be very easy to see. Mercury is one of those planets actually that very often is hard to see because of the way angles and things are working out between the Earth's orbit and planet's orbits, and what time of year it is and everything. Sometimes, even though Mercury might be at its greatest distance away from the Sun as seen in the sky, what astronomy is called elongation, and therefore you think of it's just fairly long way away from the Sun as seen in the sky, then it should be easy to see. But sometimes no, even though it could have a large elongation, it can be angled down to hoards or horizon, so it never rises very high those times. But this time it's going to come up sort of straight up, and it's going to be very very easy to see. The last thing for March Stuart is that, of course this time of the year, it's the equinops. So the equinops is going to happen on the twenty first of March or I am in Australia and some parts of the world will still be the twentieth of March, depending on what your time is on it is. The equinox, of course, is the time when the sun is rippy over the equator. In this instance, the siny is moving northwards over the equator, so that the northern hemisphere is moving towards summer and the southern hemisphere is moving towards winter. And the equinoxes the day when we get roughly equal hours of darkness and daylight. And of course we get two equinoxes, one when the SNY is moving towards the north over the equator and one six months later when it's moving out of the south. So this one in March crossing the southern hemisphere is indicates that winter's on the tway while they're friends in the north and they've got summer coming along and all their horrible snow and stuff is going to go away. And that's Stewart is the Blacker March. That senior science writer and Skyne tell Us atout the magazine contributed Jonathan Nelly and this Space. Time and that's the show for now. 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