July 9, 2021

Looking Back to the Cosmic Dawn

The Astronomy, Technology and Space Science News Podcast.
SpaceTime Series 24 Episode 78
*Looking back to the cosmic dawn
A new study claims the first stars began shining between 250 and 350 million years after the big bang 13.8 billion years ago....


The Astronomy, Technology and Space Science News Podcast.
SpaceTime Series 24 Episode 78
*Looking back to the cosmic dawn
A new study claims the first stars began shining between 250 and 350 million years after the big bang 13.8 billion years ago.
*Hubble still off line as technicians struggle to fix it
The Hubble Space Telescope remains off line following a major onboard computer crash last month.
*One Web latest launch adds to Star links satellite pollution
A Russian Soyuz rocket has successfully placed 36 British One web internet broad band telecommunication satellites into orbit.
*Skywatch July
Planet Earth reaches aphelion, The constellation Sagittarius pointing to the heart of the Milky Way galaxy, and the Delta Aquariids and Alpha Capricornids meteor showers.

For more SpaceTime and show links: https://linktr.ee/biteszHQ

Transcript

SpaceTime S24E78 AI Transcript

[00:00:00] Stuart: [00:00:00] This is SpaceTime series 24, episode 78 for broadcast on the 9th of July, 2021. Coming up on space time, looking back at the cosmic Dawn, the Hubble space telescope is still offline as technicians struggled to fix it and planet earth Rich's affiliation, all that and more coming up. On space time,

a new study claims the first stars began shining between 250 and 350 million years after the big bang 13.82 billion years ago. The findings reported in the monthly notices of the Royal astronomical society are based on a study of six of the most distant galaxies, currently known galaxies whose light [00:01:00] has taken almost the entire existence of the universe to reach here.

The authors found that the distance of these galaxies away from earth corresponded to a look back time of more than 13 billion years and era when the universe was only 550 million years old. Analyzing images from the Hubble and spitter space telescopes, the authors were able to calculate the age of each of these galaxies as ranging from somewhere around 200 to 300 million years.

And that allowed them to estimate when they first formed stars, the birth of the first ever stars known as cosmic Dawn was a key event in the evolution of the universe. See it marked the end of the cosmic dark ages. The time before the first star shot. And the ultraviolet light from those very first stars triggered the beginning of cosmic Rihanna, causation, the process that would eventually make the universe transparent and look the way it does today to [00:02:00] determine the age of cosmic Dawn, the authors analyzed Starlight from the galaxies as recorded by the hobbling spits of space telescopes.

They were looking for a marker in their spectrum, which is indicative of the presence of atomic hydrogen in their stellar atmosphere. This provided an estimate of the age of the stars. See the hydrogen signature increases in strength as the stellar population ages, but then it diminishes again when galaxies are older than around a billion years, that age dependence arises because the more massive population, three stars, which contribute to this signal burned through their nuclear fuel fairly rapidly and therefore the first to die.

One of the study's authors, Roman Maya from university college, London, and the max Planck Institute in Heidelberg says the same age indicator is used to date stars in our own stellar neighborhood in the Milky way. And it can just as easily be used to date, extremely remote galaxies in the very early universe using the syndicator astronomists could infer [00:03:00] that the six galaxies hosting these stars must've already been between 200 and 300 million years old.

In analyzing the data from Avalon and Spitzer, the authors needed to estimate the Redshift of each galaxy, which indicates their cosmological distance. And hence the lookback time at which they were being observed. Redshift is a signature of how much the universe has expanded since the big bang to achieve this.

Myra and colleagues undertook spectroscopic measurements using a full armory of powerful ground-based telescopes. These included Alma, the Atacama large millimeter submillimeter array, radio telescope, the veal, or very large telescope array, the twin Keck telescopes in Hawaii and the Gemini south telescope.

Combining these measurements allowed the team to confirm that looking at these galaxies corresponded to looking back in time to when the universe was just 550 million years old. Over the past decade, astronomers have been able to push back the [00:04:00] frontiers of what they can observe to a time when the universe was just 4% of its prison age, however, due to the limits of transparency and its atmosphere and the capabilities of the Hubble and spits of space telescopes, astronomers have now pretty well reached the limit of their abilities.

At least with the present technology. However, all that should change with the launch in November of masters, new Hubble replacement, James Webb space telescope, the authors believe James Webb will have the capability to directly witness the cosmic Dawn and the birth of the very first stars between 250 and 350 million years.

After the very beginning of the universe. This is space time. Still the cam, the Hubble space telescope is still offline. His technician struggled to fix it. And the latest one web launch adds to the growing styling, satellite pollution problem, all that, and more coming up on space time.

[00:05:00] NASA's Hubble space. Telescope remains offline following a major onboard computer crash. Last month, this year stopped all scientific observations of board, the orbiting observatory, and all attempts to identify and rectify the problem so far have failed NASA mission managers, and now preparing for procedures to turn on backup hardware engineers, to continuing to focus their efforts on the telescopes payload computer, which they think could be the issue behind the June 13th failure.

Telescope is equipped with two payload computer systems. One of which serves as a backup birth, uh, location ed on the science instrument and command and data handling unit, the systems coordinate and control science instruments, bridge communications, pass signals and store [00:06:00] operational command memories in parallel with the investigation.

NASA is prepared to test procedures on the ground to turn on backup hardware on board the spacecraft. For now the telescope itself and its science instruments remain healthy and in a safe configuration with a source of the computer problem, lying in the science instrument, command and data handling unit with a payload computer resides several systems on the unit could be the culprits technicians are currently scrutinizing the command unit science data format, which sends in formats commands and dates.

They're also looking at a power regulator within the power control unit, which is designed to ensure a steady vaunted supply to the payload computer's hardware. If one of these systems is determined to be the likely cause mission managers will need to undertake a complicated operational procedure, the switch to the backup units, and this procedure will be more complex and risky than last week's attempts, which involved switching to a backup payload, computer and memory module.

[00:07:00] The switch to the backup command unit science data format, or power regulator, several other hardware boxes on the spacecraft would also need to be switched because of the way they're all connected to the science instrument, command and data handling unit. So over the next week, engineers are reviewing and updating all the operations procedures, commands, and other related items needed to perform the switch to the backup hard way.

Well then test their execution against a high fidelity simulator here on earth. And only if that practice run works, will they try it with a real thing in orbit mind you, it's not the first time this has happened. The team performed let's switch back in 2008, which allowed hobbled to continue normal science operations.

After a command unit and science data format, a module failed back there. The fifth and final Hubble servicing mission, uh, bought the space shuttle, had ladders on STS 1 25 back in 2009, then replaced the entire site instrument, command and data handling [00:08:00] unit, including the 40 command unit and science data format, a module with a unit currently in use.

And since that mission herbalists take more than 600,000 additional observations to exceed 1.5 million during its lifetime. Hubble's work has continued to change. Science's understanding of the universe and mankind's place in it launched in 1990, where the special discovery on STS 31, the Hubble space telescope speed.

Observing the universe for over 31 years from a 541 kilometer Hyde GA centric. Low-earth orbit the telescopes actually based on keyhole spy satellites operated by the national reconnaissance office. But it's specially fitted out and positioned so that instead of looking data worth, it looks up into the cosmos by avoiding distortions in earth atmosphere.

Hubble's 2.4 meter telescope has an unobstructed view of the universe seeing stars and galaxies some more than 13.4 billion, [00:09:00] light years away. The 11,110 kilogram space observatory has contributed to some of the most significant discoveries in human history, including the accelerating expansion of the universe, the evolution of galaxies over time, and the first atmospheric studies of planets beyond our solar system.

This spacetime still the come one web adds to the growing problem of styling satellite pollution. And we'll check out the July night skies on sky. Watch all that and more stored account. On space time.

Roz cosmos has successfully placed 36 British one web internet broadband telecommunication satellites into orbit. The soil is to one, be rocket equipped with a forget upper stage was launched [00:10:00] from the  Cosmodrome in Russia's fiery. The mission is the latest and an ongoing campaign by one web to develop a constellation of an initial 650 satellites by the end of next year, the wonder in 50 kilograms, spacecraft being placed in 450 kilometer high orbits will provide 3g, LTE, 5g, and wifi coverage.

In order for one web to achieve its initial ambitions. 16 Soyuz launches have been slated between December, 2020 and the end of 2022 each launching 36 satellites. The latest launch brings one web constellation up to 254 satellites with previous launches in March, April, and may this year alone. One web is competing directly with space.

X is styling project to develop massive satellite constellations containing thousands of spacecraft providing blanket broadband coverage across the planet. The problem is so many satellites are intrusive, leaving bright star [00:11:00] truss across the sky. They not only look bad, but we're still, they cause serious problems for astronomers trying to undertake important scientific research.

And the misses between spacecraft have already occurred and deadly things will get a lot worse when there are thousands of these spacecraft up there. This is space, time.

And Tom, out of turn, I wise to the skies and check out the Celeste Jewess fee for July on Skyway. July is the seventh month of the year in both the Julie and anger Gorian calendars. And he's named after the Roman emperor Julius Caesar, who was born during the month before being called July the month was called Quinn Tillis, which is Latin for fifth.

The addition of the months, January and February broadened into that on average, July is the coldest month in the year in the Southern hemisphere, which is [00:12:00] experiencing winter. And also marks the time when earth is at affiliates, it's furthest over the position from the sun, of course, temperatures or more accurately seasons on earth.

Aren't dictated by the distance from the sun, but rather the length of a day. And hence the amount of sunlight, a given part of the earth receives, which is governed by the tote of Earth's axis. Consequently, that's why July is on average, the warmest month in the Northern hemisphere, which is currently experiencing.

During this years, they're fairly in the center of the earth will be 152 million, 100,527 kilometers from the sun. That's around 5 million kilometers further away from the sun than during perihelion. When the earth will be just 147.1 million kilometers away from the sun. This is affiliation occurred at 8 27 in the morning of Tuesday, July the sixth, Australian Eastern standard time that 6 27 in the evening, Monday, July the fifth, us Eastern daylight time and 10:27 [00:13:00] PM on July the fifth Greenwich.

Meantime, over cosmic time, these dates change that's due to variations in Earth's orbit, such as eccentricities as well as actual Tilden procession, which all follow regular cyclic patterns known as Malenka of its cycle. Eccentricity involves changes in how elliptical Earth's orbit is around the sun.

None of the planets actually orbit the sun in perfect circles. All the Venus and Neptune are the closest. Instead. They all have elongated orbits, which vary over time, as well as that of spins on an axis, which is currently till that at 23.4 degrees compared to the ecliptic Earth's orbital plan around the sun.

But this angle of tilt also changes over time influenced by among other things, the distribution of the Earth's mass and just like a spinning top. The rotational axis of the earth also changes its orientation through a process called procession changing its position in relation to fixed background stars [00:14:00] over 26,000 years.

Now all these effects impact the amount of solar radiation reaching the earth. What time it reaches the earth and consequently, the planet seasonal and climatic patterns right now, the Southern cross is at its highest point in the Southern sky and is pointing directly towards the Southern celestial pole.

The Southern cross falls within the constellation send tourists, the center, the half human half horse of Greek mythology. And the creature is holding a bow loaded with an arrow. The center, his front legs are marked by the two point stars, alpha and beta Centaurus at 4.3 light years office. And the second of the two point of stars from the Southern cross.

And he's also the nearest star system to the sun. The center was back arches over the Southern cross. And just above this is a mega Suntory, a spectacular globular cluster, visible with the unaided eye from dark locations, [00:15:00] globular clusters, tightly packed spheres containing thousands to millions of stars.

They're thought of all originally been born at the same time from the same molecular gas and dust cloud, or they're there cause of small galaxies which have been consumed by bigger galaxies through galactic cannibalism. Amiga Suntory is about 16,000 light years away. A light year is about 10 trillion kilometers.

The distance of fert on can travel in a year at 300,000 kilometers per second. The speed of light in a vacuum and the ultimate speed limit of the universe. Amiga Suntory is one of the largest and brightest of the 150 or so globular clusters known to orbit around our Milky way. Galaxy. Centaurus was one of the 48 constellations listed by the second century astronomer Ptolemy.

And it remains one of the 88 modern day constellations turning to the right or west. And you'll see the constellation, Leo, the line just above the Western horizon. [00:16:00] Its brightest star is Regulus or the little king located about 79 light years away. Regulars designated alpha Leona's is actually a five-star system organized into two pairs, Regulus a is a spectroscopic binary comprising, a special type B blue white main sequence star, some four times the mass and 288 times the luminosity of the sun and a faint companion style thought to be a white dwarf, the stellar corpse of a sun-like star.

Spectroscopic binaries of stars that can't be resolved by optical telescopes into two separate objects, and can only be separated by observing their individual spectroscopic Doppler shifts as they ordered each other. Astronomists described stars in terms of spectral types, a classification system, based on temperature and characteristics, the hottest most massive and most luminous stars and a special type of blue star.

They followed by spectral type B blue, white stars [00:17:00] and spit your type, a white stars, special type F whitish yellow stars, special type G yellow stars. That's where our son fits in spectral type K orange stars and the coolest and least massive known stars. A special type M red dwarf star. Each spectral classification is also subdivided using a numeric digit to represent temperature with zero being the hottest, the nine, the coolest, and a Roman numeral to represent luminosity.

So put all that together. And our son is a spectral type G two veer, G2 five yellow dwarf star. Also included in the Stella classification system, a spectrum types, L T and Y, which were assigned to failed stars, known as brown dwarves, some of which were actually born a spectral type M red dwarf stars that became brand wolves after losing some of the eman.

Brown dwarves Findel category between the largest planets, which can be about 13 times the mass of Jupiter and the smallest special type Embridge Wolf [00:18:00] stars, which can be 75 to 80 times, the mass of Jupiter or 0.08, solar masses located further away, a Regulus, B, C, and D, which you did main sequence stars at the opposite.

End of the constellation from Regulus is the star bitterly earners or dinner bowler, the horse's tail. It's also a luminous blue, white star, about half as bright as Regulus and the third brightest star in the constellation. Leo  has about 1.8 times the sun's mass. And about 15 times the sun's luminosity it's suspected of being a dwarf Cepheus or Delta Scotty type variable star, meaning its luminosity very slightly over a period of several hours due to pulsations on its surface.

Algebra or Gamaliel. Onus is a binary system with a visible third component. The two primary stars are located about 126 light years away and can be resolved in small backyard telescopes, both a yellow [00:19:00] giants orbiting each other every 600 earth days. The unrelated tertiary star named 40 Leona's is a yellow tin star that can be seen through binoculars.

The star traditional name algebra means forehead.  is a blue, white star, 58 light years from earth Epsilon. The oldest is a yellow giant, some 251 light years from earth and Zita Leona's is an optical triple star. The brightest component is a white giant, about 260 light years from earth while the second brightest star 39 Leona's is widely spaced and located to the south of the primary, the third and fader star, the system 35 Leona's is to the north.

Latterly Otis is a binary star system visible in medium-sized backyard telescopes. Okay. Did some 79 light years away? Letterly earnest appears to be a yellow tin start with two components, orbiting each other every 183 earth years. Finally in Leo let's look at Tahlia earners, [00:20:00] visible as a double star through binoculars.

It includes a yellow giant located some 621 light years from earth and binary, secondary staff, 54, the onus, which is actually a pair of blue, white stars, the visible and small telescopes and located some 289 light years away. The constellation. Leo also contains many galaxies, including the spiral galaxy messier 66, as well as messier 65 in NGC 36, 28, which are known as the Leo triplet located some 37 million light years away.

The Leo triplet is a somewhat distorted shape due to gravitational interactions between messier 66 and the other two galaxies, which are cannibalizing stars from Mysia 66. Eventually the Atomos stars may well form a dwarf galaxy Albany, M 66, both M 65 and M 66 are visible enlarged binoculars or small backyard telescopes, but they concentrated nuclei and elongation [00:21:00] are only visible in larger instruments.

Other bright world-known deep sky galaxies in Leo include MSCI 95 MSCI and 96 and Missy, a 105. Messy and 95 and messy and 96, a birth spiral galaxies H about 20 million light years from earth. Both look like fancy objects in small telescopes, but display they're spectacular structures in larger instruments.

M 95 is a bad spiral. Another bad spiral NGC 29 0 3 is thought to be similar in size and structure TOA and Milky way galaxy. It was discovered by William Herschel in 1784. Close to the M 95, M 96. Pair is the elliptical galaxy in 1 0 5, which is also about 20 million light years away. The constellation also contains the Leo ring, a cloud of hydrogen and helium gas orbiting two of the galaxies in the constellation, a gravitationally lensed object known as the [00:22:00] cosmic CAUTI is also a fan in layer.

Above Leo you'll find the constellation Virgo, the Greek and Roman goddess of wheat and agriculture Virgos brightest star spiker is visible above the Western horizon. It's located some 250 light years away. Spiker is Latin for ear of weight, which Virgo is holding in her hand. Spiker or alpha vaginas is the 16th brightest star in the night sky.

And he's both a spectroscopic binary and a rotating  variable, a close binary system who stars and not eclipsing, but cause apparent fluctuations in brightness because of changes in the amount of light emitting area, visible to the observer. Spike is two main stars orbit each other once every four earth days and are so close their egg shape rather than spherical, and can only be separated by this spectra.

The primary is the blue giant variable better Cepheids star. He doesn't, [00:23:00] it goes small, rapid variations in brightness. These are caused by pulsations of the star surface for it to be caused by the unusual properties of iron at temperatures of 200,000 degrees in the stellar interior. It has about 10 times the sun's mass and about seven times its diameter, the secondary star in spiker is smaller than the primary, but it's still some seven times more massive than the sun.

And it's 3.6 times the son's diameter turning to the north now. And the constellation Bertie's the herdsman or Plowman there. You'll see the bright orange, red star act terrorists or alpha. Bow-ties just above the Northern horizon. It's a red giant located just 36 light is away a bloated aging star, some 7.1 billion years old nearing the end of its life.

Although not much more massive than the sun. It's now expanded at the some 25 times the suns diameter and will soon puff off its outer gaseous envelope as a [00:24:00] planetary Nebula, revealing its wide heart stellar core, a white dwarf, which will then slowly cool over the eons of time. Another bright reddish looking star this time in the east is the red super giant and Tyrese meaning the rival of Mars because of its appearance and location in the sky, which appears to be opposite of Mars in the sky.

And terrorists is one of the biggest known stars in the universe. It's enormous 18 times the sun's mass, 10,000 times its luminosity and 883 times the sun's radius. As we mentioned in last month, sky watch word placed at the center of our solar system. Its surface would extend out close to the orbit of Jupiter despite being some 550 light years away.

And terrorists is still the 15th brightest star in the night sky. Unlike the sun or Arcturus the death event, terrorists will be far more spectacular and Terry's is there some to explode as a core collapse or tied to [00:25:00] supernova? When it does. So sometime in the next few hundred thousand years, it'll appear as bright in the earth sky as the full moon and be quite visible, even in daytime.

And Terry's has a companion star Antares be a special type blue, white main sequence star, more than seven times the sun's mass and five times its diameter and Terese is the heart of the scorpion and the constellation scorpion. Below Scorpius is the constellation Sagittarius, the Archer, which points the way to the center of the Milky way.

Galaxy Sagittarius is commonly represented as a wing center, pulling back on a bird, which is aimed at act tourists, the center of the Milky way galaxy and it's super massive black hole Sagittarius, a star lie at the Western most part of Sagittarius. Sagittarius a star is about 27,000 light years away and has some 4.3 million times the mass of our sun.

It was in July back in 2016 that the solar [00:26:00] systems Berry center moved outside the sun where it will remain until 2027. A Berry center is the gravitational center of mass of a celestial system. For example, in our earth moon system, the earth and moon actually orbit each other around a common center of gravity Berry scent.

Yeah, because the earth is so much more massive than the moon. The Berry center is always inside the Earth's radius. If it were outside the earth radius, the earth and moon would, instead of being classified as a binary planetary system like Pluto and Sharon, the solar system center of gravity or Berry center is usually located inside the sun's radius.

After all the same contains over 99% of all the solar systems. But actually the mess of the solar system is orbiting around the solar systems barrier center, which means the sun also has a very slight spiraling 12 year orbit around the Berry center and every now and then when the planet's over the positions at chest, right.

Especially with [00:27:00] Jupiter and Saturn and nearest each other, they combine gravitational interactions, move the solar systems, Berry center ever so slightly outside the sun's radius. And because Jupiter and sat and reached this alignment every 11 years, some scientists have speculated whether this could trigger the son's 11 year solar cycle.

And before you ask the Berry center is named after some guy in a base safari suit called Berry, but rather it's the ancient Greek word for heavy or center of mass. We also have two meteor showers earth of which peak, late July. There's the Southern Delta Accurate's, which are visible from mid July to mid August each year with peak activity on July the 28th and 29th.

The shower originated either from the breakup of what are now the Mazda and cracked sand grazing comets, or from the parent comet P 96, Mel Colts, the Delta Accurate's get their name because the radio apiece, the lie and the constellation Aquarius, one of the constellations, [00:28:00] brightest stars, Delta accurate.

There are two branches to the donor ackwards meteor shower, the Southern and Northern the seven Dota. Accurate's a considered a strong shower was an average between 15 and 20 meters an hour between midnight and Dawn listeners to the Southern hemisphere. Usually get the better show because the radiant is higher in the Southern sky.

Since the radiate is above the Southern horizon for Northern hemisphere, listeners videos will be seen to fan out in all directions, east, north, and west with humid, yours heading southwards, unless they're really short near the radiant, the Northern Dota Accurate's of the weakest shower peaking later in mid August with an average peak rate of about 10 meters per hour.

Meanwhile, the nearby slow and bright, alpha Capricorn its media or shower will take place from as early as July the 15th. And continue until around August the 10th. The media shower has infrequent, but relatively bright meteors and even some fireballs it's generated as the earth [00:29:00] passes through a debris trail left by the comment 1 69 pain Nate, which was originally identified as the asteroid 2002 X 12.

However it was shown to be weekly active during perihelion and was then reclassified as a comet. The media shower was created about 3,500 to 5,000 years ago, whatever half of the parent body disintegrated and fell into dust, the cloud eventually evolved into Earth's orbit, causing a shower with peak rates of that five meters an hour, and some outbursts of bright flaring comets radiating out from the constellation Capricorn towards the sound.

The bulk of the comments, the Bree won't be in Earth's path until the 24th century. At which time the alpha Capricorns are expected to become a major annual medial storm stronger than any current annual shout. Joining us now for the rest of our tour of the July night skies is Jonathan. Nalli the editor of Australian sky and telescope magazine.

Could I say Jewish? Yeah. So it's

Jonathan: [00:29:58] July more or less middle of the year. [00:30:00] It's middle of winter for us down here on the Southern hemisphere era, middle of summer for our friends up in the north. And I guess if you're in the middle of the planet, it's pretty much warm all year round, but the certainly cold and dark down here at the moment, but that's pretty good.

Um, We're on it, actually, even though it's cold and dark, the weather, the weather is actually pretty good. Normally during winter time, we don't get a lot of bad weather that comes when that comes around. When spring comes and the diet can be really nice and clear blue skies and the notch can be really nice and clear as well.

So we get non-stock scars, particularly if you are away from city lights and that kind of thing. So there's lots to see in the middle of the year, particularly for us down the south, because we're really lucky because we look into the direction of the middle of our galaxy, the Milky way, depending on your latitude, where you're out on the.

You see different things. And for us, we a very lucky winter time, the middle of our galaxy is more or less directly overhead. And there's lots of great stuff you can see towards the middle of our galaxy because we're looking right into wards. Imagine you're living in the outskirts of a city. If you look towards the city, you're going to see a lot of stuff between you and in the middle of the city.

But if you look in the other direction, further out into [00:31:00] the outskirts, you're not going to see quite so much. That's why to me that way. Yeah. Ms. Price was sort of on the outskirts. A bit of the galaxy. When we look into, towards the middle of the galaxy, there's plenty of things to say. So in the middle of the galaxies, around about the Sagittarius region, and next to that, you've got Scorpius or some people call it Scopia, lots of great stuff to say, fantastic astronomical objects.

You've got the Colombian of star classes and open star clusters and dark Nebula and Brighton. There's really interesting star patents, all sorts of things. Sagittarius, for instance, has the famous Lagunitas. And then equally famous Triffid Nebula, which is my favorite Nebula when I was growing up, probably also, because it's the terrific name I saw the movie, the other day of the Triffids and that was Aries.

Anything stick in the mind, but the triple negative is really beautiful actually. And it's sort of a snippet it's broken into three parts and it's lovely and colorful, lots of great stuff to see down there, down the Southern part of our sky at the moment, we've got the Southern cross story down there just from a year.

It's nice. So, I mean, it's really nice and high standing, almost upright just to the left. You've got the, the stars we call the two pointers, which [00:32:00] is the alpha, alpha Centura and beta Centura, which a Marine needle ice bag around the area around the Southern cross actually. And over to what's right. Is also within the Milky way.

What's right into what's left is also part of the Milky way and just like Sagittarius in school because you find lots and lots of great things to see around this area. He had a pair of binoculars and just have a squiz you don't need to telescope just binoculars a great, just to the Southern cross, for instance.

Doc patch. Like I like a big chunk has been taken out of the Milky way. This is actually a big cloud of interstellar Dustin gas, and it's been nicknamed the coal sack for obvious reasons. Been known by that name for a very long time. It really stands out if you have dark skies and you've let your eyes adapt to the dark after about 20 minutes or so, if you're in city lights, you might not see it quite so easily up in the Northern half of our sky, at least for us down here in the south, it seems pretty bare at this time of the year, but there are a couple of bright stars.

You've got this one called spot. Which is the brightest star in the constellation Virgo. Everyone's heard of Virgo. There's another star called Arcturus, which is the brightest star in the constellation Bo at T's not a constellation. Most [00:33:00] people are familiar with it's spelled double O T E S. That means the herdsman or the Plowman.

That star tourists is actually the fourth brightest star on the night sky and spike. And the other one I mentioned at the 16th brightest. So they really stand out. Spanning across the Northern half of the sky, as we see it from the south or Southern half of the sky is still down to what's the Southern horizon, as the friends in the north would see, it is part of the region that we call the Zodiac, which is rural as a Dyke or constellations are tourism Geminis, and all that sort of thing that people go on about Virgo is one of them is one of the constellations of the Zodiac.

And it's very, very large constellation to the naked eye just seems really empty. Nothing really bright about it in terms of stuff. But strong as love. They're going to, because you've got a telescope and you have a book. You'll see lots and lots of galaxies as a famous galaxy class today called the burger crossbar.

It's got lots of mucky galaxies. There's a brilliant galaxy in Virgo called M 87. No Stuart, you would've mentioned mid seven, many times on the program over the years. [00:34:00] This is the one that has a huge black hole in the Santa that astronomy has made that famous image of a couple of years ago,

Stuart: [00:34:06] finding things out about it all the time, including its fields.

This is the event horizon telescope, and they're trying to do the same thing. With Sagittarius, a star, that's the black hole at the center of the Milky way, but there it's proven to be a more difficult. Yeah, I

Jonathan: [00:34:22] think for two reasons, perhaps one is that, um, you know, there's a lot of stuff between here and the tinderbox galaxy that you go to look through.

And the other thing is what I call them. The sandbags. Then the one that's in MIT seven, even though imagine seven is a big Archie, that's a long way away. It's so big. It's so huge. I mean, it is, it's a gargantuan size galaxy and the black hole in the middle of it is equally gargantuan. So that one's in the Virgo.

There's another one in, do I go? I really love, I've always loved this one. Big spiral, very distinctive dust lane running right around the middle. And it's really symmetrical. And because of its appearance, it's been nicknamed the sombrero galaxy. If you have a look at a picture of the sombrero galaxy I'm on the [00:35:00] internet these days you'll

Stuart: [00:35:01] think galaxies, it's a beautiful galaxy fast lanes.

You get to see, you can almost see it in three me. The way we're looking at it almost there, John, but because of the way we're looking at it, there's lots of light and shadow there. You get to see yeah. If it was exactly

Jonathan: [00:35:18] edge on it, wouldn't look quite, quite as good as cause it's a little bit angled on it.

It looks really, it looks really

Stuart: [00:35:24] free. I see the little lumps and bumps in the structure of the whole thing. It is spectacular.

Jonathan: [00:35:33] Yeah, it's, it's amazing. It's amazing. Galaxy. If we can have a look at a really good picture of it, you probably won't see a sombrero in it that you want. You want to think of that? How did I get to somewhere out of that? It's because in the old days, when people were just looking through telescopes with their eyes or with the old style photography, which wasn't that crash hot compared to the fantastic electronic cameras we have today, what you saw back then was mainly the top half of the galaxy with this dark rim going.

And that made it look like a sombrero hat. The better [00:36:00] cameras you got these days also shows the bottom half nice and bright. So it looks more like, what does it look like? It's like a UFO, but let's not get into that. The fuck out of that one. But actually it's a really good story. Anyway, lots and lots of stuff to see in the constellations.

So let's now take a look at the planets to see what's happening there. Well, we'll start looking to the west just after the sun has set the beginning of July down near the Haraj and you'll see what looks to be. Bright star. Well, that's not a star. That's actually planet Venus and you can't miss it because it's really big and bright and not far above Venus, you'll see a dimmer reddish colored bar.

Well, that's also not a static the planet Mars. Okay. So you've got Venus and Mars quite close. Over there in the Western sky look far above the horizon. After the sun's gone down. Now keep an eye on these two planets as July begins, and you'll see that Venus is rising higher and higher in the sigh as each day goes past and getting closer and closer to Mars.

And from the 12th to the 15th of July, they'll be really close together. They'll only be one degree or less of an angle [00:37:00] separating themselves. More or less side by side. The moon. When we look at the moon, the moon is about half a degree across. So these two will be separated by about two moon diameters, which is pretty close as that things go in the sky.

They're not actually really close to each other out there in space just to happen, to be in the same line of sight. That's what we talk about when they decide to close in the sky and in the same sort of line of sight. Speaking of the moon, if you go out on the 12th and have a look at the moon is going to be right next to them as well.

So that should be a pretty specky site. You have Mars, Venus, and the moon. That is the month that goes on. Mars will remain roughly the same spot as it is. Scan is slowly get lower and lower in the sky, but not too much as the days go past, but fetus will continue to climb higher and higher up the horizon.

Now, the end of most planet mercury is always pretty hard to spot. Actually, it doesn't really rise very high above the horizon normally. So if you have any trees or Hills or buildings or anything in the way, chances are. Most of the time out of view for you. But this month you have to be an early riser and you have to be that before Dawn, as mercury is, is, will be above the Eastern horizon before the [00:38:00] sun comes up.

But only for the first couple of weeks, and it's going to be pretty low down even at its highest point and about seven or eight degrees above the horizon. And as the weeks go by, we dropping lower and lower towards the horizon, and then it'll get lost in the glare of the sun as the sun stops. Now the other two big planets are the three biggest planets in the solar system, Saturn and Jupiter.

Well, they're evening what we call evening objects at the moment, we can see them in the evening. They're rising above the Eastern horizon. Not too long after the sun has gone down and therefore they're visible for pretty much all of the night satins rising around about 7:30 PM at the start of the month, four star guises that our athletic treat of Sydney.

Fuel. It's a latitude of New York in north America. It'll be different for you because it's summertime up there. It's winter time down here. So seven's rising about 7:30 PM, July or people mid-latitudes in the Southern hemisphere. By the end of the month, it'll be about oh two hours earlier than that. So election, if you're already over the horizon, as the sun goes down, as the sky stops to get dark that's Saturn and Jupiter follows it up above the horizon of half an hour and a half flight.

So they're not too far [00:39:00] apart in the sky. Second comes up first. Well, that was about an hour and a half later. Next month, both of these planets, again, to reach what astronomers call opposition. And this has been a planet and the sun directly on opposite sides of us. So one direction there, you've got the sun and the other direction, 190 degrees.

Opposite is the planet. This means that thrust standing on the surface of us as the sun's going down the. Kinda it's rising above the horizon over there in the practical upshot of that is that if you'd like to do snug rising, it means that the planet's going to be up all night. That's from the, from the moment of sunset all the way through to bone, it's going to be visible where the permitting opposition's also more or less the same time as when a planet is closest to the earth.

Even though that's a very long way away for both Jupiter and Saturn, this still be closest to the earth and therefore being closer to elevation. Than they normally do. And that means if you, um, if you have a look through a telescope, you'd be able to make out more detail than you normally would. So yeah, next month, August should be really, really good astronomers again.

And look forward to that. Both of these planets coming to [00:40:00] opposition

Stuart: [00:40:00] in the same month, that's Jonathan, Nalli the editor of Australian sky and telescope magazine. And don't forget if you're having trouble getting your copy of Australian sky and telescope magazine from your usual retailer because of the current lockdown and travel restrictions, and always get a print or digital subscription and have the magazine delivered directly to your letterbox or inbox.

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Jonathan Nally

Editor Australian Sky & Telescope Magazine

Our editor, Jonathan Nally, is well known to members of both the amateur and professional astronomical communities. In 1987 he founded Australia’s first astronomy magazine, Sky & Space, and in 2005 became the launch editor for Australian Sky & Telescope. He has written for other major science magazines and technology magazines, and has authored, contributed to or edited many astronomy, nature, history and technology books. In 2000 the Astronomical Society of Australia awarded him the inaugural David Allen Prize for Excellence in the promotion of Astronomy to the public.