Astronomical Observations and Announcements

tahanson43206 · 2020-04-26 10:40:24

The story at the link below should be of interest to one or two NewMars members:

https://www.cnn.com/2020/04/26/world/al … index.html

I am ** particularly** interested in the alien asteroid that is in a stable retrograde orbit with Jupiter.

That is ** not ** a retrograde orbit AROUND Jupiter! It is a retrograde orbit (with respect to Jupiter) around the Sun.

To my way of thinking, this would/should make it automatically a candidate for a human research outpost. While the asteroid would necessarily pass by Jupiter once every 11+ years, it would spend the rest of that time at the orbit of Jupiter but well away from it, and therefore well positioned to provide all sorts of services to a growing Solar Civilization. Those services would start with communications and serving as an emergency shelter for Solar System mariners in distress, but would and should include a scientific observatory of major significance, as well as whatever activities make economic sense as the civilization grows.

(th)

Void · 2020-04-26 11:28:30

That is a very interesting article tahanson43206.

If you don't mind I will comment. I may just a tiny bit go to panspermia, but will mostly just stick with the main topic.

If we considered some imaginary snapshots of our stars development, perhaps we could choose 3 pictures.
-When it was a spinning cloud of gas and dust.
-When it was a proto-star with a disk.
-How it is now.

Then I would ask, what would happen in each case if Oumuamua passed into our solar system at each stage. We already know about what would happen in the now snapshot.

For the proto-star with a disk, then the object may very well pass through the disk twice, maybe hit something else, or maybe just get a coating of condensed materials with some dust. There would be a lot of variables. But for an object to be captured then it is not just gravitation that is acting on it. And the gravitation pattern is different than the now situation because as it approached the disk, it would be gravitationally pulled towards it. After it passed through the disk, the disks gravity would tug on it against it's direction of travel. So, that would be an interesting potential capture method. If the object did finally get locked into the local gravity field, it might pass through the disk repeatedly, and would likely have it's orbital plane merge into the disk's orbital plane.

As for a spinning cloud of gas and dust: The object would enter this cloud a bit like it were the atmosphere of a planet I think. So in addition to gravity there could be lots of drag. In addition, if there were condensable substances, then the traveling object might accumulate dirty ices on it's surface, so it's mass would increase. If this were true, then gravitation, drag, and accumulation would potentially work together to capture the object.

So, as I see it the universe is to some degree, a random number generator. Star systems eject objects, and particularly baby star systems may capture them. It would be something like cloud seeding. You can get more condensation action if seeds are injected into the potential condensation site.

And so in part this could explain why there are so many different types of planetary setups. From the beginning, rather random objects are injected into the formation situation.

It appears that if a supernova has exploded nearby, then https://en.wikipedia.org/wiki/Aluminium-26 can be included in the condensation process. If so, then the condensing objects can be kept warm enough from the radioactive decay, to form ice covered mudballs, that eventually may turn to rock. But while they are mudballs, they may be friendly to microbial life. (If it is seeded to them by some process).

So then we might have the stars in a star nursery spitting up on each other, or rather throwing mud balls into each others cribs.

If somehow a rogue planet with life on it had been captured into one of the proto-stars clouds, then possibly would be one way that life could travel from an old star system to spark it in a star nursery.

https://www.wired.com/2011/02/steppenwolf-planet/

In this case an object would have to strike the captured rogue planet and eject infected materials into the nursery.

Going back to the main topic, I would say depending on when the object was captured it may or may not have a coating of our own local materials over it. However, if one of this are coated with our local materials, because it arrived early in our stars formation, if there is a crater, the alien materials might be exposed there.

That just what I currently think. I do not claim to be an expert.

Thanks for the topic (th)

Last edited by Void (2020-04-26 12:02:27)

tahanson43206 · 2020-04-26 11:41:18

For Void re #2

Thank you for giving this new topic your preliminary endorsement, and a challenging set of questions for NewMars forum members to consider.

This is a good time to remind readers of this forum, who are not currently members, that there are currently no limits of any kind to membership.

The kind of person we would ** invite ** to join the forum, and to contribute to the content archived here, would be someone motivated by an interest in the overall theme of the forum, and in the objectives of the Mars Society as a whole.

In this case, to the best of my knowledge there are no professional astronomers present in the membership.

To the best of my knowledge, there are not even any ** amateur ** astronomers present in the membership.

Persons with knowledge of astronomy, at the professional, academic or even amateur level would be welcome to participate in discussion of articles posted in this topic.

(th)

tahanson43206 · 2021-07-05 11:15:42

The story at the link below ought to be a good fit for the NewMars forum:

https://www.msn.com/en-us/news/technolo … hp&pc=U531

The study suggests that the light-sail powered cube satellite could be sent into space ahead of time, essentially 'parked' near the sun until the orbit of the ISO is determined.
Once it's found, the trajectory of the sail could be targeted to the perihelion - the point in the orbit at which it's closes to the sun - to figure out the right velocity to intercept the ISO.
It would happen in four phases: 'Earth to perihelion, ISO orbit alignment, around the Sun to solar system escape velocity, approach and intercept with the ISO.'
The sail craft would have an escape velocity of more than six astronomical units (AU) per year, or roughly 558 million miles.
'This would permit rapid response to a new ISO discovery and an intercept within 10 AU from the sun,' the researchers added.
The distance between the Earth and the sun is one astronomical unit, or approximately 93 million miles.
If it were a five-year mission, the light sail-powered cube sat could catch and study the ISO, while a ten-year mission could even bring back a sample, the researchers added.
Both technologies - cubesats and light-sails - have been proven in space.
The Mars Cube One, launched in March 2018, was one of the first interplanetary small satellites.
Conversely, lightsail missions in 2013 - from Earth to Venus - and in 2021 - in Earth orbit - have already taken place.
Given the close proximity to the sun, the solar sail would need to be able to manage heat.
If it were aluminum coated with Kapton, it could withstand the heat from the sun due to the high melting point of aluminum (approximately 930 Kelvin) if it were within 0.15 AU of the sun.
The benefits of such a spacecraft would not only allow astronomers to better study ISOs and potentially even learn their origin, but it could also be used for planetary defense, planet formation and learning more about the solar system, among other benefits.
'The scientific return from such investigations is invaluable, as comparative studies between an ISO sample return with solar system asteroid and comet sample returns can help us understand the conditions and processes of solar system formation and the nature of the interstellar matter,' the researchers wrote in the study.
'With many new ISOs expected the significance of such an investigation is of the highest priority.'
The findings have been published in the pre-print journal arXiv and can be read here.
Read more

This concept should be of interest to Quaoar?

(th)

Void · 2021-11-01 12:17:51

Well I did not find a reference to Planet X or Planet 9.

Still this will do, as this is likely a large Dwarf Planet, larger than Pluto, and ~Three times further out.

I guess this is a real discovery. These days BS is becoming more common.

https://www.space.com/1373-object-bigge … lanet.html

The new object, temporarily named 2003 UB313, is about three times as far from the Sun as is Pluto.
"It's definitely bigger than Pluto," said Brown, a professor of planetary astronomy. The object is round and could be up to twice as large as Pluto, Brown told reporters in a hastily called NASA-run teleconference Friday evening.

It would be interesting, if the disturbance supposed to indicate a new outer planet was actually a bunch of dwarf planets that we have not yet discovered?

If Fusion power shows up that would create a really interesting future for humans, if they make it off planet in any numbers.

Done.

tahanson43206 · 2021-11-05 09:10:55

https://www.cnn.com/2021/11/04/world/as … index.html

The article at the link above reports on the decisions and recommendations of the Decadal Survey.

The survey committee agreed with NASA that the agency should discontinue operations of SOFIA, or the Stratospheric Observatory for Infrared Astronomy, in 2023. The modified Boeing 747 carries a 2.7-meter (106-inch) reflecting telescope and flies into the stratosphere. While the unique aircraft has led to some interesting scientific discoveries, the authors didn't think the mission was worth the cost to continue it.
The growing concern over the frequent launches of megaconstellations of satellites is also addressed in the report.
"Scientifically the greatest impact is on searches for Near Earth Objects," the authors wrote. "The National Science Foundation should work with the appropriate federal regulatory agencies to develop and implement a regulatory framework to control the impacts of satellite constellations on astronomy and on the human experience of the night sky."

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GW Johnson · 2021-11-05 11:57:59

Just some astronomical observations I ran across recently. From AIAA’s email newsletter “The Daily Launch” for Thursday 11-4-2021:

Asteroid Passes By Earth Without Being Detected Until It Was Gone
SPACE (11/3) reports that an “asteroid about the size of a refrigerator shot past Earth last week, and astronomers didn’t know the object existed until hours after it was gone.” Scientists “were unaware of the object, dubbed Asteroid 2021 UA1, because it approached Earth’s daytime side from the direction of the sun.”

This was yet another dayside approach from sunward that absolutely cannot be detected with any sort of telescope on the Earth or in orbit about the Earth. Such objects can only be detected by something located more sunward than the Earth, looking out away from the sun. See “Asteroid Threats” 30 August 2020 on “exrocketman”.

Water Detected In Galaxy 12.8B Light Years From Earth
USA Today (11/3) reports that scientists “have discovered evidence of water in a galaxy roughly 12.8 billion light-years from Earth, making it one of the most distant discoveries of water in the universe.” The galaxy, SPT-311-58, was discovered in 2017 by researchers using the Atacama Large Millimeter/Submillimeter Array in Chile. The scientists from the University of Illinois at Urbana-Champaign found the water molecules from SPT-311-58 to be especially notable because the galaxy originated from an early stage in the universe’s life, “when it was only 780 million years old.” The presence of water in the galaxy “proves molecular life began not too long after the Big Bang.”

This is an example of a too-large a claim made from too little information. It proves the water for life as we know it was there not long after the Big Bang. That proves NOTHING about the existence of said life where that water was found, which claimed proof of life is what the wording means. I see this way too often.

Curiosity Rover Discovers Organic Molecules On Mars
The Daily Mail (UK) (11/3) reports that NASA’s Curiosity rover “has discovered previously unknown organic molecules, ammonia and benzoic acid, on Mars that could be possible indicators of ancient life.”

This is a harbinger of things to come. The scientists who were discredited for claiming they found microbe fossils inside the Martian meteorite Allan Hills 84001 will eventually be proven to have been right. They were discredited for claiming “too much” even though they didn’t, but events since have been slowly proving them right.

Sun Produced Three Coronal Mass Ejections Since Monday
SPACE (11/3) reports that the sun has produced three coronal mass ejections (CMEs) since Monday. On Monday and Tuesday, “a sunspot designated AR2887 unleashed two of these outbursts. Then, later in the day on Tuesday (Nov. 2), a second sunspot called AR2891 produced a CME as well.” The third ejection is moving more quickly than the two others, “so it swept through all of one previous CME and part of the other.” Scientists predicted that the resulting CME would arrive at Earth Wednesday “and produce geomagnetic storms beginning on Thursday (Nov. 4).”

This is exactly why any manned spacecraft outside the Earth’s magnetic field absolutely must have a radiation shelter or shielding for its crew. See “Space Radiation Risks: GCR vs SFE” 5 October 2018 on “exrocketman”.

Atacama Desert Site Of Ancient Comet Impact
CNN (11/3) reports that researchers believe the Atacama Desert in Chile “was the site of an ancient comet explosion intense enough to create giant slabs of silicate glass.” The minerals found in the desert glass “matched up with particles collected by NASA’s Stardust mission, which sampled a comet known as Wild 2.” Study author and Brown University Professor Emeritus of Geological Science Pete Schultz said, “This is the first time we have clear evidence of glasses on Earth that were created by the thermal radiation and winds from a fireball exploding just above the surface.”
The Daily Mail (UK) (11/3) reports that the glass fragments collected by Brown University researchers “contained exotic minerals such as cubanite and troilite only found in meteorites and other extraterrestrial rocks.”

This is yet another example of why a deflection technology and the means to deliver it, are necessary. See “Asteroid Threats” 30 August 2020 on “exrocketman”.

GW

tahanson43206 · 2022-01-16 12:06:14

https://www.nbcnews.com/science/space/a … -rcna11830

Supernovas are the final stages of many stars, and they are responsible for seeding interstellar clouds of gas and dust with “heavy” chemical elements. The clouds seeded by the explosions then coalesce into younger stars, like the sun, and the elements — such as carbon, oxygen, silicon and iron — are incorporated into their planets.
Previously, the “old age” of massive stars has been almost impossible to observe, said Matt Nicholl, a lecturer in physics and astronomy at the University of Birmingham in the United Kingdom. “Before now, we’ve never been able to study this crucial phase directly,” he said in an email.

The report at the link above provides details about painstaking research that led to discovery of a red giant 130 days before it performed it's "supernova" maneuver, which seeds the region nearby with heavy elements.

By coincidence, I've been looking at an image of the telescope in one of my webcam displays.

Hawaii has been blanketed in snow at this time of the year.

(th)

SpaceNut · 2022-01-16 12:27:10

Some of those elements are short lived while others will still be present is ever reducing quantities as the half life continue to happen. The more stable elements would become the what we would use for civilizations to come.

The news has been documenting a few rocks flying by the earth recently. All of which could do quite a bit of damage if it should be a direct hit.

tahanson43206 · 2022-01-18 11:03:46

This JPL web site is sourced by TheSkyLive, which is the site visited each day in preparation of the Mars Business Calendar post.

https://ssd.jpl.nasa.gov/horizons/

Horizons System
About
App
Manual
Tutorial
Time Spans
News
About Horizons
Horizons Cartoon
Pierre! Next time, use the Horizons Ephemeris Service...
The JPL Horizons on-line solar system data and ephemeris computation service provides access to key solar system data and flexible production of highly accurate ephemerides for solar system objects (1,169,179 asteroids, 3,778 comets, 211 planetary satellites {includes satellites of Earth and dwarf planet Pluto}, 8 planets, the Sun, L1, L2, select spacecraft, and system barycenters). Horizons is provided by the Solar System Dynamics Group of the Jet Propulsion Laboratory.
Documentation is available via the “Manual” tab above. Available time-spans for objects provided by Horizons can be viewed via the “Time Spans” tab above. When requesting an ephemeris for a specific object, you should ensure the requested time(s) are within the available time-span for that object.
The Horizons system can be accessed via a variety of interfaces: web, command-line, email, and an API. Each interface is described below.
Web Interface
The web-interface to Horizons is available via the “App” tab above. New users are encouraged to use the tutorial and reference the manual when needed.
Providing nearly all capabilities of the primary command-line interface, it does not provide the following.
Small-body Population Searches (use the Small-Body Database Query Tool as an alternative).
Custom Close-Approach Tables
Command-Line Interface
The command-line (primary) interface to Horizons can be accessed directly by connecting to “horizons.jpl.nasa.gov” via port 6775. This will initiate a text-only “VT100” terminal command-line session that accesses all Horizons functions. You will be taken through a series of prompts that will ask you questions needed to generate the desired information. To initiate such an interactive session from a UNIX/LINUX system terminal, type the following:
telnet horizons.jpl.nasa.gov 6775
Once connected, type ? from any prompt for help.
Most MacOS and Windows telnet client programs have a dialog box in which the port number (6775) can be entered. If after connecting to “horizons.jpl.nasa.gov” you are prompted for a login name (not necessary for Horizons), it means the port 6775 request was not passed along by the software on your end. Some Windows terminal software does not fully implement the telnet protocol and does not send port numbers, even if you enter them.
Email Interface
The Horizons system can be accessed using email to submit batch-style input files. Instructions on how to access the email server, including a complete detailed example, is available by sending an email message to horizons@ssd.jpl.nasa.gov with the subject “BATCH-LONG”. You can also access instructions via this link.
IMPORTANT: Please be sure your email client is sending content as plain ASCII text. Failure to do so may result in no response from the system or an error message, even when your job-content appears perfect from within your email client. Modern graphical e-mail systems often insert hidden font and formatting codes that Horizons cannot interpret. A helpful guide to suitably configure some email clients for plain-text is available via this link. However, e-mail requests may now be most practical for those working in a UNIX/Linux/MacOS programmatic command-line and text editor environment.
API
The Horizons system can be accessed using an API. Instructions for using the API are available via the API server. The API is useful for programatic control of the Horizons system.

(th)

tahanson43206 · 2023-11-14 14:16:13

Today I asked ChatGPT(4) about the current Solar Conjunction, as reported in the Calendar topic. ChatGPT mentioned the interval of 26 months between conjunctions, and I immediately recognized the similarity to the interval between Hohmann Transfer Orbit opportunities. The next one is in fall of 2024. I am guessing that the Hohmann Transfer Orbit window opens some predictable number of Earth days after a Solar Conjunction. However, ChatGPT was unable to find historical data to support this hypothesis. It suggested using Python to search existing databases of historical data, and that is certainly possible.

If there is a member with access to astronomic databases, or to sophisticated prediction software, I'd appreciate a post in this topic supporting or falsifying my hypothesis. It ** should ** be possible to prepare a table from historical data, in this format:

Solar Conjunction - Hohmann Transfer Orbit Window Start - elapsed Earth days between

All we have to go on right now are the two data points:

Solar Conjunction is in progress now and ... next Hohmann Transfer window starts late next year.

Update later .... I found this report of the previous Solar Conjunction:

Mars at solar conjunction
This event is not observable at present from Mansfield. Never attempt to point a pair of binoculars or a telescope at an object close to the Sun
THU, 07 OCT 2021 AT 23:35 EDT (03:35 UTC)
768 DAYS AGO
Dominic Ford, Editor
From the Outer Planets feed
Tags: Solar Conjunction Objects: Mars

(th)

tahanson43206 · 2023-11-15 08:59:37

Today ChatGPT was busy so I asked BARD about the positions of the Sun and Mars, as reported by theskylive.com.

2023/11/15 at 14:06 UTC
Mars: 15h 24m 01.3s Decl: -18° 42' 39.6"
Sun: 15h 20m 49.6s Decl: -18° 25' 19.5"
The separation between Mars and the Sun as seen from Earth on 2023-11-15 14:06 UTC is 0.9968980038939641 degrees.
Sun is above the other.

The two objects do not show up in the same display panel in theskylive.com tracker pages.

BARD has estimated the separation as (about) 1 degree of Declination.

The highest object in the tracker panel for Mars today is TYC 6176-1096-1 at Declination -18 degrees 42 minutes 40.4 seconds

The lowest object in the tracker panel for the Sun today is TYC 6174-1128-1 at Declination -18 degrees 44 minutes 16.6 seconds

What these figures mean is that the tracker panel is able to show both objects. The problem appears to be in Right Ascension.

I'll save this post and take a look at Right Ascension ...

The tracker page that shows Sun today has RA 15h 23m 1l.0s on the left border and RA 15h 18m 51.4s on the right

The tracker pages that shows Mars today has RA 15h 25m 58.9s on the left, and RA 18m 21m 46.9s on the right.

I moved the mouse in the Mars tracker page to the upper right corner, and the Sun is indeed within the Declination spread of the page. However, the Sun is off the page to the right.

I went back to the Sun tracker page, and Mars is indeed just below the Sun in Declination, but off the page to the left in RA.

It seems possible that the two objects will appear on the same tracker page as the Conjunction proceeds.

Update a bit later: By laying out a drawing of the two panels with the respective coverage in RA, I determined that there is already a significant overlap in Right Ascension. This led to confirmation that are great number of objects (stars and galaxies) are already shared by the two panels.

Tomorrow I would expect the sharing to increase.

(th)

tahanson43206 · 2023-11-16 07:18:39

The Sun and Mars are present in the same panel of theskylive.com/mars-tracker

This situation will persist for an Earth Day or two, so NewMars members have an opportunity to see for themselves as the two bodies line up as seen from Earth.

This is the ONLY time in the 26 month cycle when we humans can be absolutely ** sure ** we know where Mars is in the sky!

230,321,746 km [23.9 km/s] is the distance of Mars from the Sun today.

Earth is (of course) on the opposite side of the Sun, at a distance of 378,262,902 km

The Earth-Mars distance is NOT the maximum possible. The distance has been DECREASING in recent Earth days.

If anyone is interested the changes of Earth-Mars distance are recorded in the daily Calendar report.

Update on 2023/11/17 .... distance: 230,130,190 km [23.9 km/s]
The Sun is above and to the right of Mars in the tracker window today.

(th)

tahanson43206 · 2023-11-17 07:22:02

The Sun and Mars are present in the same panel of theskylive.com/mars-tracker

Sun/Mars distance is 230,130,190 km [23.9 km/s]

(th)

tahanson43206 · 2023-11-18 07:45:32

The Sun passed above Mars in the previous 24 hour period .... The two objects remain visible in the same panel at theskylive.com/mars-tracker

Sun/Mars distance at 13:00 UTC was 229,938,381 km [23.9 km/s]

Earth/Mars distance today is 377,818,419 km.

This conjunction will occur again (about) 26 months from now.

(th)

tahanson43206 · 2024-11-12 07:50:01

Today (2024/11/12) on Earth is New Year's Eve on Mars. In a few hours, Mars Year 38 will begin, as Mars crosses it's Vernal Equinox and begins a new Year with longitude 0 (zero). I was curious about the history of how Earth astronomers chose the Year Zero for Mars, and found this article from Scientific American:

https://www.scientificamerican.com/arti … -new-year/

The UniverseFridays
November 8, 2024
Happy New Year! (If You’re a Martian)
The Martian new year arrives with the Red Planet’s vernal equinox. Explaining why requires a deep dive into celestial mechanics and Earth’s calendrical history
By Phil Plait
The planet Mars against a starry sky
Alones Creative/Getty Images
Astronomy
The Universe
Stay connected to The Universe: Get email alerts for this weekly column by Phil Plait
You may think it’s a few weeks early to celebrate the new year, but that’s only because you’re Earthist: November 12, 2024, marks the new year for Mars, when the calendar turns the page from 37 to 38.
And here I am, still putting 37 on all my checks.
Why would anyone pick November 12 as New Year’s Day for Mars? And why does our official reckoning of Martian time set the eons-old Red Planet only in its 38th year? The answer involves a combination of natural cycles and the human need to impose order via somewhat arbitrary timekeeping—pretty much like on Earth.
Here on our home planet, most countries use the Gregorian calendar to keep track of the year. This was first adopted in 1582 (although it took quite some time to spread around the world) and is your standard 12-month calendar—365 days every year, with a bonus day added on every fourth year (a “leap” year). The Gregorian calendar starts on January 1 as a holdover from its predecessor, the Roman Empire’s Julian calendar; to honor the god Janus, Julius Caesar proclaimed that day to be the year’s first.
As an astronomer, I might wish we marked the first day of the year using a date of some astronomical significance. The problem there is Earth stubbornly refuses to play nice with any sort of organized calendar. For example, our planet’s path around the sun is an ellipse, or oval shape. That means there is a point in time when it gets closest to the sun, which we call perihelion. That seems like a natural date for the start of a new year.
But Earth’s orbital shape changes subtly every year because of the gravitational influence of the other planets, altering the exact time of perihelion. Another tweak to perihelion’s timing comes from Earth’s moon, which tugs on our planet to make it wobble a bit as we co-orbit the sun. These make perihelion an unworkably complicated way to start a calendar, even though perihelion also happens to occur in January. (Aphelion—when Earth is farthest from the sun—occurs in July.)
If you know a little bit more about astronomy, you might try to tag the new year with the equinoxes or solstices. These dates are based on Earth’s axial tilt, our planet’s roughly 23-degree pitch relative to the plane of its orbit (which is why you always see classroom globes tilted over on their stand). The June solstice, for example, occurs when the planet’s north pole is tipped most toward the sun, which happens on or about the 21st of that month every year. (Note that this is in winter for people in the Southern Hemisphere, which is why astronomers tend to shy away from calling it the “summer solstice.”)
Astronomers prefer to measure everything in the sky relative to the March equinox, also called the vernal (“relating to spring”) equinox as a holdover from Northern Hemisphere–focused timekeeping. There are many ways to think about the March equinox, but astronomers think of it as the time when the sun’s position on the sky crosses the celestial equator, the projection of Earth’s equator onto the sky. That’s a handy point in time and space to use for measuring things like the positions of the planets and stars.
Curated by Our Editors
Illustration shows Earth in deep space. It is split at the equator, with the hemispheres pulled apart. A clock with a second hand is visible on the equatorial cut surface.
But again, because of the changing shape of Earth’s orbit, using that to mark the new year would be a hassle. The calendar date changes every year, adding unwieldy layers of chronological complexity.
So what does all this have to do with Mars?
Early in the 20th century, as humans began scrutinizing Mars with more powerful telescopes, we saw global changes sweep across that planet in sync with its changing position in its orbit. Then, as exquisite in situ observations emerged from our probes sent to the Red Planet, it became clear we needed some sort of Mars calendar.
Such a calendar would have to be very different from ours. The most obvious reason is that Mars is farther out from the sun and takes almost two Earth years to complete a single orbit around our star; a Martian year is about 687 Earth days!
A Mars day—called a sol, to distinguish it from an Earth day—is also a little bit longer than our terrestrial one, lasting 24 hours, 39 minutes and 35 seconds. There are about 668 sols in a Martian year.
But these differences are actually liberating because they free us from our historic legacy of arbitrary sociopolitical machinations. At Mars, we were able to get a fresh start, defining when we wanted the year to begin essentially from scratch.
So planetary scientists decided to start the Martian new year at the time of the planet’s vernal equinox. Like Earth, the spin axis of Mars is tipped over relative to its orbit, and Mars even has a relatively Earth-like axial tilt of about 25 degrees. That means it has seasons similar to ours, creating the global changes earlier astronomers had witnessed. As temperatures rise in the Martian spring, dust storms arise, and some grow so large they can cover much of the planet. The onset of summer in a given hemisphere heats the respective polar ice cap, which shrinks in size as it sublimates (turns from solid to gas).
Why not use the equinox as a starting date, then? If we have to choose a date, that one makes as much sense as any.
If only things could be so simple. Earth’s orbit around the sun is very nearly a circle, and the seasons all last about three months. But Mars’s orbit around the sun is decidedly elliptical. When the planet is closest to the sun (in winter in its northern hemisphere) its orbital speed is faster than when it’s furthest (in northern summer), and combined with the oval orbital shape, this means the seasons have significantly different lengths. Northern spring is 194 sols long, while summer is 178, autumn is 142 and winter is 154 sols in duration.
These odd seasons would make living on Mars weird. I mean, it would of course be hard: the suffocatingly thin atmosphere, high radiation levels, lack of quick and easy access to supplies from Earth, and so on would all make it extremely difficult to eke out a life there. But the wonky calendar would be a constant source of extra irritation.
And what of the year number—the bizarre fact that our Martian calendar has so far only advanced to Year 38? Scientists decided to mark Year 1 as the time a huge dust storm raged across the planet’s surface in 1956—one of the most notable events on another planet during the early space age. The vernal equinox for that Martian year occurred on April 11, 1955, so that’s now accepted as the planet’s first New Year’s Day. To make things less ambiguous, scientists also defined Year 0 as starting on the previous equinox, May 24, 1953. This prevents any weirdness like that of the Gregorian calendar, which, because it has no Year 0, creates strange situations such as new centuries starting on years ending with 01 instead of 00. (The 21st century, for instance, began on January 1, 2001.)
Put this all together, and you’ll see that Year 38 on Mars begins on November 12, 2024, in the earthly Gregorian calendar, at around 16:00 coordinated universal time, or UTC (11 A.M. EST). Get your party hats and champagne ready!
And don’t forget: when the clock ticks down to zero, it’s time to sing Ares Lang Syne.
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Phil Plait is a professional astronomer and science communicator in Virginia. He writes the Bad Astronomy Newsletter. Follow him online.
More by Phil Plait

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tahanson43206 · 2024-11-12 08:13:19

From Post #16

Article by Phil Plait

And what of the year number—the bizarre fact that our Martian calendar has so far only advanced to Year 38? Scientists decided to mark Year 1 as the time a huge dust storm raged across the planet’s surface in 1956—one of the most notable events on another planet during the early space age. The vernal equinox for that Martian year occurred on April 11, 1955, so that’s now accepted as the planet’s first New Year’s Day. To make things less ambiguous, scientists also defined Year 0 as starting on the previous equinox, May 24, 1953. This prevents any weirdness like that of the Gregorian calendar, which, because it has no Year 0, creates strange situations such as new centuries starting on years ending with 01 instead of 00. (The 21st century, for instance, began on January 1, 2001.)

(th)

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