moon-jupiter

I just wanted to share this gorgeous photograph – Jupiter and all four of its Galilean moons clearly visible, behind our own Moon with the sunlight illuminating the bumps and ridges on its surface. I love photographs like this. Sometimes it’s a pleasant reminder of how small our world is, to look up at night and see the other planets in the night sky. And to remember that we now know what they look like up close.

Unfortunately, I have no idea who the photographer is, and neither Google Images nor Tineye are being much help. The best I can do is to track it back to this tumblr page, which lists no other source. If you know where this photograph came from originally, please let me know so I can credit the photographer properly!

 

Advertisements
Aside | Posted on by | Tagged , , | Leave a comment

The Planet Quandary I – The Sacred 8

So this is the first part of my series of analyses and perspectives on the ongoing planet debate. Honestly, I can’t believe it’s been like, a decade already. Which is probably the main reason I’m going into some detail on this. Admittedly, the scientific community at large is somewhat infamous for spending a long time ruminating over things. Not least because, whether or not they admit it, a lot of scientists don’t really like change. Ironic but true.

Anyway, this first in this blog series is largely in reaction to a post by Ethan Siegel on his blog, Starts With a Bang. If you have a few minutes, you may want to go and read it – I’ve been reading Ethan’s writings for several years now. He’s great at explaining things from the ground up, and his articles are well structured without skimping on the detail. However, in this case, I think he’s wrong.

This concerns the definition of planets, and what does and does not constitute a planet, scientifically speaking. I’m also going to reiterate what I said in my introductory post that Pluto is not the point here, even if I may use it as a convenient example.

The full definition given by the IAU of what a planet actually is is… complicated. I’ll go into more detail on that in my next article. For now, I’m just going to concentrate on one thing. A principle outlined in a paper by Margot (2015) which gives a line in the planetary sand, demarcating what is and is not a planet.

My own redrawn version of this figure is here:

(There’s a larger version with all my annotations here.)

Seems fairly clear, doesn’t it? Anything above the line is a planet. Simples! This is essentially a function of whether or not a planet has “cleared its orbit” of other material – things which haven’t aren’t allowed to be planets.

Trouble is, this is a paper written in 2015 to justify a decision by the IAU in 2006. To my knowledge, situations such as this are rather prone to confirmation bias. Particularly when devising a rule so carefully tailored to our own Solar System. In fact, it’s interesting how firmly people want to hold the belief that there are 8 planets in the Solar System and absolutely no more. The sacred 8. A highly exclusive club, from which all vagrant small round objects are banned.

My biggest problem with this definition and its mathematically defined line in the space sand, is that it isn’t constant. The definition of an object changes, dependent on where it is exactly. And call me old fashioned, but I like my definitions to be… well… definite.

To reiterate: The definition of what an object is changes according to its location.

If you move a planet to a different orbit, it will transform into a different object. Yes, this is a mathematical consequence of this definition. And it has a number of ramifications…

Changing Identities

If you were to move Earth to an orbit greater than ~140 AU from the Sun, it will cease to be a planet. While this admittedly is unlikely to happen, barring a cataclysmic event, it has implications. Earth-sized planets are typically considered unambiguously to be planets, seeing as we live on one. But by this definition, if we find any Earth-sized objects out beyond the Kuiper Belt, they may not be planets.

Meanwhile, if you were to move Pluto inwards to an orbit somewhere between Mercury and Venus, it would be a planet. Which seems to contradict the “Pluto is too small” argument that so many people always seem to make.

You’re Simply Not Close Enough

The not-a-planet line actually crosses the x-axis in this graph around 0.04 AU, which means that literally anything orbiting inside that line may be a planet – even tiny objects like Ceres, Enceladus, or a comet which is at hydrostatic equilibrium. For the record, according to NASA’s small body database, there are over 1420 objects which pass closer to the Sun than 0.04 AU. Of course, these don’t dominate their orbit in terms of mass. But their presence does call into question whether or not Earth’s orbit should be considered “cleared”.

Planets or Moons?

It’s worth also considering the moons of the Solar System. If Earth’s moon was orbiting the Sun at the same distance Earth is now, it would be considered a planet. Meanwhile, if Titan were orbiting the Sun instead of Saturn, it wouldn’t be a planet, despite being larger than the Moon. If we were to replace Jupiter with its moon Ganymede (more massive than Titan), it would be just barely too small. It misses the planet line by between 0.008 and 0.011 Earth masses, depending on whether it’s at perihelion or aphelion.

Part-Time Planets

In fact, given that planetary orbits are elliptical by definition, this means that anything orbiting too close to that magic line may be a part-time planet, achieving planethood once every orbit when it’s fortunate enough to be sufficiently close to its parent star.

This has some interesting implications as well, for people hunting for the elusive “Planet 9“. Formerly known as Planet X, but now it wouldn’t be number 10. Interestingly, it may not always be number 9 either. Planet 9, if it exists, is predicted to have an elliptical orbit with a perihelion of 200 AU and an Aphelion of 1200 AU (which is why it’s shown in two places on that plot up there). Checking this against Margot’s magic planet line, it turns out that this is just enough to be a “planet” for its entire orbit.

It suddenly feels a little suspicious that Mike Brown, who goes by the rather unsubtle twitter name of @PlutoKiller, predicted this as Planet Nine’s most distant point. I have to wonder what will happen to this definition if it turns out that Planet Nine is slightly further away. Will people start to rethink this definition if the Solar System contains an object which ceases to be a planet once per orbit?

On a final note, Margot’s line in the sand is touted as being scalable and applicable to any star/planet system. So I did what anyone else would to investigate this. I downloaded the entire NASA Exoplanet Archive to take a look.

Out of a total of 3485 listed records, I found 1070 objects with known mass, orbital semimajor axis, and host star mass – mass of the host star was important to scale things so I could plot them on the same graph. Turns out, the overwhelming majority of these are indeed “planets” by the IAU definition. Though as anyone who works in exoplanet detection will tell you, our methods are biased overwhelmingly to detect things which are either very large or very close to their parent star. Below a certain size and above a certain orbital semimajor axis, we’re largely blind.

All the same, there are a few outliers on that plot. The low mass ones are pulsar planets, which everyone always forgets about anyway. But there are undeniably two super-Earth sized planets in the data which aren’t allowed to be real planets under Margot’s definition. In addition, two Jupiter-sized planets are borderline cases which may be only part-time planets depending on how eccentric their orbits are.

As I always say, a good hypothesis will become stronger the more you try to break it. Unfortunately, the way I see it, the IAU’s definition of a planet has cracks in it. It seems strong at first, but it has weaknesses.

My prediction is that as our telescopes improve and the planet hunters keep doing their thing, we’ll start to find more and more objects which are inexplicably not allowed to be planets.

Perhaps then, everyone might consider a better definition. In the meantime, I’ll let Mars here describe my feelings on the matter.

It’s fair to say that every change, major or minor, that’s ever happened in science hasn’t been without its opposition. In my opinion, this is not necessarily a bad thing. I’ve been, at various points, on both sides of the debates. Sometimes, it can stimulate much needed discussion and conversation, but other times it can stand in the way of progress. It’s a double edged sword.
Consider also that very hot things tend to melt, and that liquids reach hydrostatic equilibrium very easily. Water droplets, for instance, are at hydrostatic equilibrium. Taking this to its most ludicrous extreme, a small globule of molten glass in a circular orbit around the Sun at 0.02 AU would be classified as a planet if there was nothing else orbiting there.
By the way, it wasn’t included in the archive, but the mass of PSR B1257+12 is believed to be about 1.4 solar masses.

Posted in astronomy, space | Tagged | 4 Comments

The Moon and The Meteor

Did you know it’s actually possible to see a meteor crash land on the moon? You need to be very lucky to do so, but it’s not uncommon. After all, both Earth and the Moon are being continually pelted with meteoritic material. Most of it is barely larger than dust, but occasionally a few larger objects leave their mark.

I’ve actually been lucky enough to see this once myself. When I was just a kid living out in the countryside under dark skies, I used to have a telescope. The Moon was always an easy target to look at, so I used to point my telescope there quite often. One night just as I was about to finish up for the night, I actually saw a bright spot appear on the Moon’s surface ever so briefly.

At first, I wasn’t entirely sure what it was I’d seen. After doing a little reading, I realised it must’ve been a meteor impact. It wasn’t quite as bright as the one highlighted in this video, but it was definitely the same thing. If it had been on the Moon’s sunlit side, I wouldn’t have seen it at all. Strangely enough, this video is one of the few I’ve ever seen which show the same thing I saw that night.

I still consider myself rather lucky to have actually seen an event like that, small though it may have been. It’s little things like that which have always kept me fascinated with astronomy.

Posted in astronomy | Tagged , | Leave a comment

The Planet Quandary

As some of my readers will probably know quite well, every astronomer’s favourite argument of what exactly a planet is has been drifting in and out of discussions for years now. This delightful nest of conversational wasps was recently shaken up again by none other than Alan Stern, the scientist behind NASA’s New Horizons mission to Pluto. And I’m very much inclined to take his side in the discussion.

You wouldn’t think it would be that difficult to define something like a planet, seeing as we live on one. However, you’d be mistaken. In science, we like to have good definitions of things. They’re sometimes surprising and may take things into account that you wouldn’t normally consider. This is the way of science, after all. Unfortunately… Well. To say that scientists don’t always agree on things would be an overwhelming understatement.

Stern’s argument is that planets should be defined geophysically, as he outlines in a recent paper. To me, this makes a lot of sense – even if it would suddenly mean that the Solar System is full of 110 planets. If this sounds like a lot to teach kids in school, remember that there were 151 Pokémon in the original game. This would include, among others, such places as Titan, Ganymede, Ceres, Enceladus, and Earth’s moon.

Everyone seems to focus on Pluto as the centre of the argument, but to me it’s incidental. I don’t care so much about Pluto’s planetary status. I do care about the fact that the IAU’s definition of a planet is needlessly convoluted and all kinds of problematic. Nonetheless, this is the decision which the IAU council came to.

In the words of Nick Fury…

This is a big topic, and I have a lot to discuss on it. This includes summarising conversations I’ve had with various people. So I’m not going to try and tackle it all at once. Instead, I’m going to write a series of blog posts (probably 4 or 5) on various aspects of the whole planet not-a-planet debacle.

I would, of course, appreciate any discussion and feedback anyone else wants to give on the matter as and when I post these. Even if you disagree with what I’m saying. Perhaps especially if you disagree with what I’m saying.

Let’s break this all down and see what we can build from the pieces.

Posted in astronomy, space | Tagged | 3 Comments

π = 3.14159 26535 89793 23846 26433 83279 50288 41971 69399 37510 58209 74944 59230 78164 06286 20899 86280 34825 34211 70679 82148 08651 32823 06647 09384 46095 50582 23172 53594 08128 48111 74502 84102 70193 85211 05559 64462 29489 54930 38196 44288 10975 66593 34461 28475 64823 37867 83165 27120 19091 45648 56692 34603 48610 45432 66482 13393 60726 02491 41273 72458 70066 06315 58817 48815 20920 96282 92540 91715 36436 78925 90360 01133 05305 48820 46652 13841 46951 94151 16094 33057 27036 57595 91953 09218 61173 81932 61179 31051 18548 07446 23799 62749 56735 18857 52724 89122 79381 83011 94912 98336 73362 44065 66430 86021 39494 63952 24737 19070 21798 60943 70277 05392 17176 29317 67523 84674 81846 76694 05132 00056 81271 45263 56082 77857 71342 75778 96091 73637 17872 14684 40901 22495 34301 46549 58537 10507 92279 68925 89235 42019 95611 21290 21960 86403 44181 59813 62977 47713 09960 51870 72113 49999 99837 29780 49951 05973 17328 16096 31859 50244 59455 34690 83026 42522 30825 33446 85035 26193 11881 71010 00313 78387 52886 58753 32083 81420 61717 76691 47303 59825 34904 28755 46873 11595 62863 88235 37875 93751 95778 18577 80532 17122 68066 13001 92787 66111 95909 21642 01989 38095 25720 10654 85863 27886 59361 53381 82796 82303 01952 03530 18529 68995 77362 25994 13891 24972 17752 83479 13151 55748 57242 45415 06959 50829 53311 68617 27855 88907 50983 81754 63746 49393 19255 06040 09277 01671 13900 98488 24012 85836 16035 63707 66010 47101 81942 95559 61989 46767 83744 94482 55379 77472 68471 04047 53464 62080 46684 25906 94912 93313 67702 89891 52104 75216 20569 66024 05803 81501 93511 25338 24300 35587 64024 74964 73263 91419 92726 04269 92279 67823 54781 63600 93417 21641 21992 45863 15030 28618 29745 55706 74983 85054 94588 58692 69956 90927 21079 75093 02955 32116 53449 87202 75596 02364 80665 49911 98818 34797 75356 63698 07426 54252 78625 51818 41757 46728 90977 77279 38000 81647 06001 61452 49192 17321 72147 72350 14144 19735 68548 16136 11573 52552 13347 57418 49468 43852 33239 07394 14333 45477 62416 86251 89835 69485 56209 92192 22184 27255 02542 56887 67179 04946 01653 46680 49886 27232 79178 60857 84383 82796 79766 81454 10095 38837 86360 95068 00642 25125 20511 73929 84896 08412 84886 26945 60424 19652 85022 21066 11863 06744 27862 20391 94945 04712 37137 86960 95636 43719 17287 46776 46575 73962 41389 08658 32645 99581 33904 78027 59009 94657 64078 95126 94683 98352 59570 98258 22620 52248 94077 26719 47826 84826 01476 99090 26401 36394 43745 53050 68203 49625 24517 49399 65143 14298 09190 65925 09372 21696 46151 57098 58387 41059 78859 59772 97549 89301 61753 92846 81382 68683 86894 27741 55991 85592 52459 53959 43104 99725 24680 84598 72736 44695 84865 38367 36222 62609 91246 08051 24388 43904 51244 13654 97627 80797 71569 14359 97700 12961 60894 41694 86855 58484 06353 42207 22258 28488 64815 84560 28506 01684 27394 52267 46767 88952 52138 52254 99546 66727 82398 64565 96116 35488 62305 77456 49803 55936 34568 17432 41125 15076 06947 94510 96596 09402 52288 79710 89314 56691 36867 22874 89405 60101 50330 86179 28680 92087 47609 17824 93858 90097 14909 67598 52613 65549 78189 31297 84821 68299 89487 22658 80485 75640 14270 47755 51323 79641 45152 37462 34364 54285 84447 95265 86782 10511 41354 73573 95231 13427 16610 21359 69536 23144 29524 84937 18711 01457 65403 59027 99344 03742 00731 05785 39062 19838 74478 08478 48968 33214 45713 86875 19435 06430 21845 31910 48481 00537 06146 80674 91927 81911 97939 95206 14196 63428 75444 06437 45123 71819 21799 98391 01591 95618 14675 14269 12397 48940 90718 64942 31961 56794 52080 95146 55022 52316 03881 93014 20937 62137 85595 66389 37787 08303 90697 92077 34672 21825 62599 66150 14215 03068 03844 77345 49202 60541 46659 25201 49744 28507 32518 66600 21324 34088 19071 04863 31734 64965 14539 05796 26856 10055 08106 65879 69981 63574 73638 40525 71459 10289 70641 40110 97120 62804 39039 75951 56771 57700 42033 78699 36007 23055 87631 76359 42187 31251 47120 53292 81918 26186 12586 73215 79198 41484 88291 64470 60957 52706 95722 09175 67116 72291 09816 90915 28017 35067 12748 58322 28718 35209 35396 57251 21083 57915 13698 82091 44421 00675 10334 67110 31412 67111 36990 86585 16398 31501 97016 51511 68517 14376 57618 35155 65088 49099 89859 98238 73455 28331 63550 76479 18535 89322 61854 89632 13293 30898 57064 20467 52590 70915 48141 65498 59461 63718 02709 81994 30992 44889 57571 28289 05923 23326 09729 97120 84433 57326 54893 82391 19325 97463 66730 58360 41428 13883 03203 82490 37589 85243 74417 02913 27656 18093 77344 40307 07469 21120 19130 20330 38019 76211 01100 44929 32151 60842 44485 96376 69838 95228 68478 31235 52658 21314 49576 85726 24334 41893 03968 64262 43410 77322 69780 28073 18915 44110 10446 82325 27162 01052 65227 21116 60396 66557 30925 47110 55785 37634 66820 65310 98965 26918 62056 47693 12570 58635 66201 85581 00729 36065 98764 86117 91045 33488 50346 11365 76867 53249 44166 80396 26579 78771 85560 84552 96541 26654 08530 61434 44318 58676 97514 56614 06800 70023 78776 59134 40171 27494 70420 56223 05389 94561 31407 11270 00407 85473 32699 39081 45466 46458 80797 27082 66830 63432 85878 56983 05235 80893 30657 57406 79545 71637 75254 20211 49557 61581 40025 01262 28594 13021 64715 50979 25923 09907 96547 37612 55176 56751 35751 78296 66454 77917 45011 29961 48903 04639 94713 29621 07340 43751 89573 59614 58901 93897 13111 79042 97828 56475 03203 19869 15140 28708 08599 04801 09412 14722 13179 47647 77262 24142 54854 54033 21571 85306 14228 81375 85043 06332 17518 29798 66223 71721 59160 77166 92547 48738 98665 49494 50114 65406 28433 66393 79003 97692 65672 14638 53067 36096 57120 91807 63832 71664 16274 88880 07869 25602 90228 47210 40317 21186 08204 19000 42296 61711 96377 92133 75751 14959 50156 60496 31862 94726 54736 42523 08177 03675 15906 73502 35072 83540 56704 03867 43513 62222 47715 89150 49530 98444 89333 09634 08780 76932 59939 78054 19341 44737 74418 42631 29860 80998 88687 41326 04721 56951 62396 58645 73021 63159 81931 95167 35381 29741 67729 47867 24229 24654 36680 09806 76928 23828 06899 64004 82435 40370 14163 14965 89794 09243 23789 69070 69779 42236 25082 21688 95738 37986 23001 59377 64716 51228 93578 60158 81617 55782 97352 33446 04281 51262 72037 34314 65319 77774 16031 99066 55418 76397 92933 44195 21541 34189 94854 44734 56738 31624 99341 91318 14809 27777 10386 38773 43177 20754 56545 32207 77092 12019 05166 09628 04909 26360 19759 88281 61332 31666 36528 61932 66863 36062 73567 63035 44776 28035 04507 77235 54710 58595 48702 79081 43562 40145 17180 62464 36267 94561 27531 81340 78330 33625 42327 83944 97538 24372 05835 31147 71199 26063 81334 67768 79695 97030 98339 13077 10987 04085 91337 46414 42822 77263 46594 70474 58784 77872 01927 71528 07317 67907 70715 72134 44730 60570 07334 92436 93113 83504 93163 12840 42512 19256 51798 06941 13528 01314 70130 47816 43788 51852 90928 54520 11658 39341 96562 13491 43415 95625 86586 55705 52690 49652 09858 03385 07224 26482 93972 85847 83163 05777 75606 88876 44624 82468 57926 03953 52773 48030 48029 00587 60758 25104 74709 16439 61362 67604 49256 27420 42083 20856 61190 62545 43372 13153 59584 50687 72460 29016 18766 79524 06163 42522 57719 54291 62991 93064 55377 99140 37340 43287 52628 88963 99587 94757 29174 64263 57455 25407 90914 51357 11136 94109 11939 32519 10760 20825 20261 87985 31887 70584 29725 91677 81314 96990 09019 21169 71737 27847 68472 68608 49003 37702 42429 16513 00500 51683 23364 35038 95170 29893 92233 45172 20138 12806 96501 17844 08745 19601 21228 59937 16231 30171 14448 46409 03890 64495 44400 61986 90754 85160 26327 50529 83491 87407 86680 88183 38510 22833 45085 04860 82503 93021 33219 71551 84306 35455 00766 82829 49304 13776 55279 39751 75461 39539 84683 39363 83047 46119 96653 85815 38420 56853 38621 86725 23340 28308 71123 28278 92125 07712 62946 32295 63989 89893 58211 67456 27010 21835 64622 01349 67151 88190 97303 81198 00497 34072 39610 36854 06643 19395 09790 19069 96395 52453 00545 05806 85501 95673 02292 19139 33918 56803 44903 98205 95510 02263 53536 19204 19947 45538 59381 02343 95544 95977 83779 02374 21617 27111 72364 34354 39478 22181 85286 24085 14006 66044 33258 88569 86705 43154 70696 57474 58550 33232 33421 07301 54594 05165 53790 68662 73337 99585 11562 57843 22988 27372 31989 87571 41595 78111 96358 33005 94087 30681 21602 87649 62867 44604 77464 91599 50549 73742 56269 01049 03778 19868 35938 14657 41268 04925 64879 85561 45372 34786 73303 90468 83834 36346 55379 49864 19270 56387 29317 48723 32083 76011 23029 91136 79386 27089 43879 93620 16295 15413 37142 48928 30722 01269 01475 46684 76535 76164 77379 46752 00490 75715 55278 19653 62132 39264 06160 13635 81559 07422 02020 31872 77605 27721 90055 61484 25551 87925 30343 51398 44253 22341 57623 36106 42506 39049 75008 65627 10953 59194 65897 51413 10348 22769 30624 74353 63256 91607 81547 81811 52843 66795 70611 08615 33150 44521 27473 92454 49454 23682 88606 13408 41486 37767 00961 20715 12491 40430 27253 86076 48236 34143 34623 51897 57664 52164 13767 96903 14950 19108 57598 44239 19862 91642 19399 49072 36234 64684 41173 94032 65918 40443 78051 33389 45257 42399 50829 65912 28508 55582 15725 03107 12570 12668 30240 29295 25220 11872 67675 62204 15420 51618 41634 84756 51699 98116 14101 00299 60783 86909 29160 30288 40026 91041 40792 88621 50784 24516 70908 70006 99282 12066 04183 71806 53556 72525 32567 53286 12910 42487 76182 58297 65157 95984 70356 22262 93486 00341 58722 98053 49896 50226 29174 87882 02734 20922 22453 39856 26476 69149 05562 84250 39127 57710 28402 79980 66365 82548 89264 88025 45661 01729 67026 64076 55904 29099 45681 50652 65305 37182 94127 03369 31378 51786 09040 70866 71149 65583 43434 76933 85781 71138 64558 73678 12301 45876 87126 60348 91390 95620 09939 36103 10291 61615 28813 84379 09904 23174 73363 94804 57593 14931 40529 76347 57481 19356 70911 01377 51721 00803 15590 24853 09066 92037 67192 20332 29094 33467 68514 22144 77379 39375 17034 43661 99104 03375 11173 54719 18550 46449 02636 55128 16228 82446 25759 16333 03910 72253 83742 18214 08835 08657 39177 15096 82887 47826 56995 99574 49066 17583 44137 52239 70968 34080 05355 98491 75417 38188 39994 46974 86762 65516 58276 58483 58845 31427 75687 90029 09517 02835 29716 34456 21296 40435 23117 60066 51012 41200 65975 58512 76178 58382 92041 97484 42360 80071 93045 76189 32349 22927 96501 98751 87212 72675 07981 25547 09589 04556 35792 12210 33346 69749 92356 30254 94780 24901 14195 21238 28153 09114 07907 38602 51522 74299 58180 72471 62591 66854 51333 12394 80494 70791 19153 26734 30282 44186 04142 63639 54800 04480 02670 49624 82017 92896 47669 75831 83271 31425 17029 69234 88962 76684 40323 26092 75249 60357 99646 92565 04936 81836 09003 23809 29345 95889 70695 36534 94060 34021 66544 37558 90045 63288 22505 45255 64056 44824 65151 87547 11962 18443 96582 53375 43885 69094 11303 15095 26179 37800 29741 20766 51479 39425 90298 96959 46995 56576 12186 56196 73378 62362 56125 21632 08628 69222 10327 48892 18654 36480 22967 80705 76561 51446 32046 92790 68212 07388 37781 42335 62823 60896 32080 68222 46801 22482 61177 18589 63814 09183 90367 36722 20888 32151 37556 00372 79839 40041 52970 02878 30766 70944 47456 01345 56417 25437 09069 79396 12257 14298 94671 54357 84687 88614 44581 23145 93571 98492 25284 71605 04922 12424 70141 21478 05734 55105 00801 90869 96033 02763 47870 81081 75450 11930 71412 23390 86639 38339 52942 57869 05076 43100 63835 19834 38934 15961 31854 34754 64955 69781 03829 30971 64651 43840 70070 73604 11237 35998 43452 25161 05070 27056 23526 60127 64848 30840 76118 30130 52793 20542 74628 65403 60367 45328 65105 70658 74882 25698 15793 67897 66974 22057 50596 83440 86973 50201 41020 67235 85020 07245 22563 26513 41055 92401 90274 21624 84391 40359 98953 53945 90944 07046 91209 14093 87001 26456 00162 37428 80210 92764 57931 06579 22955 24988 72758 46101 26483 69998 92256 95968 81592 05600 10165 52563 7567

Aside | Posted on by | Tagged | 1 Comment

Journey to Jupiter

Amateur astronomers really do accomplish some fantastic things. Things like this gorgeous little video!

Between December 2014 and March 2015, 91 astronomers from around the world took over 1000 photographs of our planet’s largest sibling and arranged them into this video. 250 Jupiter days, for your viewing pleasure. Honestly, I’m pretty stunned.

The mastermind behind all of the image stacking and projection building is Peter Rosén, who can be found on both YouTube and Vimeo.

Posted in art, astronomy | Tagged , | Leave a comment

Wanderers, by Erik Wernquist. Relax for 4 minutes and let your mind drift with a short film. Oh, and click the button to watch it in full screen. Trust me, it’s entirely worth seeing in full definition.

Aside | Posted on by | Tagged , , | Leave a comment

8 fabulous holiday destinations on Venus!

a-slice-of-venusIt’s that time of year when those of us who live on islands high in the northern hemisphere are really tired of cold, rainy weather. So why not plan a trip away somewhere? And what better destination than Venus?

Supernova Condensate Travel brings you all the very best advice on solar system vacations and adventure holidays, and we would like to recommend our neighbouring planet of Venus as the perfect travel destination for that little getaway you’ve been planning.

After all, with an average surface temperature of 462°C, the weather on Venus is always hot. What’s more, with an atmospheric water content of just 20 ppm, you’ll never have to cancel any outdoor activities because of rain! Not water rain anyway. But there’s no need to worry about being on a planet with a sky full of lethal sulfuric acid. Venusian acid rain falls only as virga and always evaporates long before it reaches the surface.

Of course, the weather on Venus may be a little cloudy, but with solar irradiance almost twice as high as Earth, it’s never dreary even with the constant cloud cover. Even better, you’ll never need to wear sunscreen! Perfect! Before you pack your bags though, why not have a look at these 8 great places to visit on our nearest neighbouring planet?

1. Baltis Vallis

Just because Venus doesn’t have much water, doesn’t mean it has no rivers! Or river channels anyway. Winding through the grand southern plains of Atalantia Planitia is Baltis Vallis – the longest river channel in the entire solar system! Baltis Vallis stretches out for almost 7000 km (a bit longer than the Nile here on Earth), with an average width of 1-3 km. Click here to see an image highlighting the start and end of a 600 km stretch of it.

baltis-vallis

It’s thought to be an old lava channel, meaning the lava that made it must have been very low viscosity. Carbonatite lava is one possibility. Baltis Vallis is quite old – the original channel was longer, but it’s been disrupted somewhat over time. In fact, parts of the channel we see today appear to flow uphill, suggesting that Venus’ surface has seen some upheaval since the channel was formed.

Thankfully for any travellers, it’s unlikely such upheavals will happen today, as no volcanism or tectonic activity has been observed on Venus. Why not take the Baltis Vallis challenge and attempt to traverse the entire length of the channel?

Please note: Lack of observations of volcanism and tectonic activity do not mean such events do not occur on Venus. Supernova Condensate Travel warns that all visitors to Venus be wary of earthquakes and eruptions at all times.

2. Meitner Crater

meitner-craterMuch like on Earth, impact craters are rare on Venus. A few do exist however, such as Meitner, named after a personal hero of ours here at Supernova Condensate Travel.

A fantastic example of a multiring crater, Meitner sprawls out with a diameter of 149 km. Views from the rings of massifs at the crater’s rim afford spectacular views through the dense venusian atmosphere of the peak ring basin. Even more impressive during the rainy season, with sulfuric acid virga adding to the unique atmosphere of this picturesque spot. Why not explore the splayed layer of ejecta surrounding the crater? Or perhaps climb the central uplift for a great camping spot!

Please note: Camping on Venus may be inadvisable due to extreme weather conditions. Supernova Condensate Travel takes no liability for tents or other camping equipment melting due to extreme heat.

3. Fotla Corona

fotla-corona

One of the many treasures of the planet Venus is the vast number of coronae dotting the surface. A corona is a volcanic feature only found on two worlds in the solar system – Venus, and the Uranian moon Miranda. Formed when hot material wells up underneath the surface of a planet, these huge volcanic crowns make excellent places to go hiking, particularly for those who may not be well suited to hike the more rugged terrain found elsewhere, such as the more challenging Venusian tesserae.

Located in Venus’ Nsomeka Plains, the dramatic Fotla Corona has it all – from smooth plateau regions for gentler hiking to a complex network of fractures for those who enjoy a more challenging route. This fracture network was probably formed as lava (possibly related to the nearby volcanic domes) accumulated within fractures in the planet’s surface, eventually leading to a collapse event which caused some of Venus’ most stark and beautiful terrain.

Please note: Supernova Condensate Travel would like to remind you that hiking on Venus is inadvisable without highly specialised equipment to protect from extremes of heat and pressure. Such equipment may not actually be possible with existing human technology.

4. Maat Mons

maat-monsOf the plentiful volcanoes covering the surface of Venus, Maat Mons is the tallest, affording panoramic views across Aphrodite Terra’s beautiful Atla Regio highlands. Rising 5 km above the surrounding plains. It’s the second highest peak on the planet, high enough that some believe it may be belching out SO₂ and CH₄ through plinian eruptions, accounting for the variations seen in those two gasses in Venus’ middle atmosphere. Tourists considering Maat Mons as a destination may be reassured though, that no active volcanism has been observed here.

The summit of Maat Mons is home to a vast caldera, some 28 by 31 km in size. Nested within it are at least 5 smaller collapse calderas. Additionally, to the southeast, there’s a small chain of additional collapse calderas, around 3–5 km in size. It’s thought that these calderas were created by at least 2 major collapse events in Maat Mons’ history. Luckily for hiking holidays, these events seems to be in the past. Despite searches for evidence of current volcanic acitivity, no eruptions have ever been seen at Maat Mons. Like most of the Venusian volcanoes, Maat Mons is a shield volcano, and is actually very similar in both size and shape to the big island of Hawai’i. Albeit with slightly hotter weather.

5. Siddons Patera

siddons-patera

Many planets in the solar system contain paterae – irregular crater-like surface features caused by volcanic activity – including Io and Mars. But why travel all the way to Io, when Venusian paterae offer such majestic landscapes right on your planetary doorstep?

Siddons Patera is the perfect example of such a location. Located in the North of Venus, conveniently near Ishtar Terra, Siddons Patera is a caldera with much to offer. If you’re a photographer or artist looking to capture the dramatic landscape, the collapsed lava tubes surrounding Siddons Patera offer breathtaking views. They’re also great fun to explore, if you’re planning a family trip! Who knows what exciting adventures may await in the lava tubes which remain structurally intact?

Please note: Traversing uncollapsed Venusian lava tubes is a high risk activity which should not be attempted without expert guidance. Supernova Condensate Travel accepts no liability for any tourists involved in cave-ins or for unexpected volcanic activity.

6. Guinivere Planitia Lowlands

lowlands-guinivere-planitia

There are few more beautiful placesto spend Springtime than the scenic lowlands of Guinivere Planitia. Not that Springtime has much meaning on a planet with only 3° of axial tilt. But, of course, it’s the attitude that counts!

The broad, sweeping lowland plains of Guinivere Planitia are always a sight to behold, with their many scattered pancake domes – a type of geological feature specific to Venus. These broad, volcanic domes tend to be found clustered together in the lowland plains around Venus’ more rugged terrain. Good news for mountain climbers too – Venusian pancake domes may be named after a flat fried foodstuff, but they’re between 10 – 100 times as large as any volcanic dome found on Earth!

7. Skadi Mons

Speaking of mountain climbing, Venus is an excellent destination for it. None of the low gravity on other worlds – with a surface gravity of 8.87 m/s, Venusian gravity is nearly as strong as the gravity back home on Earth, giving a true climbing experience.

In the heart of Ishtar Terra, you’ll find the majestic Maxwell Montes. This mountain range is one of only three features on the entire planet which isn’t named after women. But fear not – Skadi Mons takes her name from the goddess Skaði in Norse mythology. Skaði is a goddess of mountains and skiing. Perfect to give her name to Venus’ highest peak!

Yskadi-monsou might not think there’s much skiing to be done on Venus. After all, surely skiing needs snow? As it happens, Venusian mountains have snow all of their own! Unlike Earth though, this snow isn’t made of water ice. The mountains of Venus are thought to be capped with snow made from heavy metals – bright, shining mountain caps, made from galena and bismuth sulfide, glinting in the afternoon sunlight as it filters through the clouds. Even better because, with such long days on Venus, an afternoon could last for your entire vacation!

Please note: It is uncertain whether or not any kind of skiing can be done using heavy metal sulfide crystals. Supernova Condensate Travel takes no responsibility for any injuries or poisoning acquired while attempting to ski on Venusian snow.

8. Phoebe Regio

One of the first places on the surface of Venus to be seen by human eyes. Or robot eyes, anyway. This was the chosen landing site of the Soviet Venera landers, and they could not have chosen a more scenic spot. While Phoebe Regio may lack the snowcapped mountains or majestic tesserae of other Venusian holiday destinations, it’s not a place to be overlooked. Located in the lowlands, away from Ishtar and Aphrodite Terrae, the craggy terrain of Phoebe Regio is an excellent place to go camping.

Why not throw a party there to celebrate the end of such a successful holiday on scenic Venus? Even better, with a single Venus day lasting the same as over 116 Earth days, an all-night party on Venus is quite an event. There ain’t no party like a Venusian party, because a Venusian party genuinely does not stop for weeks on end!

Please note: 7 Venus days is equivalent to 2.2 years back on Earth. Some confusion may therefore arise if you notify your workplace that you’ll be “only staying for a week.” Supernova Condensate Travel accepts no responsibility for termination of employment based on misunderstandings such as these.

phoebe-regio

Most images are courtesy of NASA/Magellan.
The final image of Venus’ surface is a remastered image created with Soviet Venera pictures by the quite excellent Don P. Mitchell. Image manipulations are created by myself, using clouds from an image by mistagregory/Wikimedia Commons.

Posted in astronomy, space | Tagged , , | Leave a comment

Cosmic Latte

If you ever load up this blog from a slower connection, you may notice that before the background image loads, the HTML background for the page is a kind of off-white vaguely magnolia-ish colour. There is actually a reason for this.

That colour is this colour – and this colour is the average colour of the Universe.
Its official name is Cosmic Latte.

cosmic-latte

Karl Glazebrook and Ivan Baldry determined this colour in 2002, using the light from over 200,000 galaxies. The average colour was this soft creamy colour which wouldn’t look out of place on the walls of a downtown coffeeshop. For any graphic designers reading, the hex value of this colour is #FFF8E7.

Amusingly, a few other names were suggested for this colour, including Univeige, Astronomer Almond, and Skyvory.

Name aside, the colour may be familiar to anyone who enjoys looking at astronomical images. The cores of galaxies are often a very similar colour!

slice-of-andromeda

This image is a tiny version of the largest image ever taken of the Andromeda galaxy. You can see it in all its glory at APOD. Credit: NASA, ESA, J. Dalcanton, B. F. Williams, L. C. Johnson (U. Washington), PHAT team, R. Gendler

Posted in art, astronomy | Tagged , | Leave a comment

Seems like a lot of things around here are either not working or in need of being updated. A consequence, I suppose, of having being absent for so long. If you happen to find anything glitchy or broken, please feel free to leave a comment here letting me know, and I’ll try to fix it.

Aside | Posted on by | Leave a comment