Kategoriarkiv: Astronomi

Star greater than the Milky Way?

At a party a few days ago, I was standing outside with a couple of friends viewing the incredible night sky when we started talking about the magnificent vastness of space. One of them brought up having heard of a single star that was greater than the entire Milky Way galaxy – which is pretty freaking huge! I was skeptical, seeing as from what I know of stars there is a top limit of both mass and size, when the star will collapse onto itself, exploding into a supernova. Stars can be incredibly huge, but as large as the Milky Way, which itself contains several hundred billion stars?

See the Earth dwarfed by our Sun, and it dwarfed by the ginormous VI Canis Majoris, the greatest star discovered. (ill. D. Jarvis)

Stars can indeed be pretty huge, but it’s impossible to keep track of the big numbers. The standing fact, I confirm after a few minutes of researching, is that while stars are huge, the galaxy is a lot huger. In the end it’s like comparing an A2 poster to North America – surely a poster can be pretty big, but an entire continent plays in a different league altogether.

Our own star, the Sun, is about 1 392 000 km in diameter, 109 times the size of the Earth. That’s a tad smaller than your random star in the universe, and there are lots of different kinds of stars both smaller and greater. Our Sun is very much a dwarf, and there are many stars that are several orders of magnitude larger. The greatest star discovered in the universe is VY Canis Majoris, a red hypergiant 2000 times the size of the Sun!

Our Sun as compared to the largest known star. (ill. Mysid)

That’s large. That’s large enough to stretch through a great deal of our solar system. If VY Canis Majoris for some reason suddenly replaced our star, the entire Earth would be engulfed in its flames, as would Mercury, Venus, Mars, the Asteroid Belt, Jupiter and Saturn. Cool, but not nearly as big as the galaxy – that’s several hundred billion times larger.

Illustrations: ”Comparison stars and planets” by David Jarvis (CC BY-SA 3.0), ”Sun and VY Canis Majoris” by Mysid (public domain).

The Beautiful Cosmos: M106

A beautiful picture of the M106 galaxy, lost in the vastness of space.

Messier 106 (also known as NGC 4258) is a spiral galaxy in the constellation Canes Venatici. It was discovered by Pierre Méchain in 1781. M106 is at a distance of about 22 to 25 million light-years away from Earth. It is also a Seyfert II galaxy, which means that due to x-rays and unusual emission lines detected, it is suspected that part of the galaxy is falling into a supermassive black hole in the center. NGC 4217 is a possible companion galaxy of Messier 106.

André van der Hoeven

Books of March 2012

These are the books read or listened to in March.

  • Philip Plait: “Death from the Skies! The Science Behind the End of the World” (2008)
    • Balancing between depression, amusement and fascination, astronomer Phil Plait (of badastronomy.com) lists a number of ways in which the race of humanity could be wiped out – everything from asteroid impact and sunburn to alien attack and black holes.
  • Mayfair Mei-hui Yang: “Gifts, Favors, & Banquets: the Art of Social Relationships in China” (1994)
    • A more non-academic friendly discussion on guanxi than the other books I’ve read on the topic. Yang deals with the more practical issues and less with causes and such, which is both good and bad. Definitely a necessary book for anyone who wants to delve into Chinese social relations.
  • Yanjie Bian: “Work and Inequality in Urban China” (1994)
    • Bian is probably the academic who has researched guanxi most of anyone, and this is his summary of surveys, interviews and official statistics, outlining how guanxi works and what impact it has on the Chinese urban society. A goldmine, albeit with somewhat debatable results which I critisise in an upcoming article this summer.
  • Arthur Conan Doyle: “The Adventures of Sherlock Holmes” (1892)
    • Twelve of Sherlock Holmes stories, most if not all very intriguing. Also the first book that I’ve ever read entirely on a smart phone.
  • Douglas Adams: “The Hitchhiker’s Guide to the Galaxy” (1979) book
    • After reading the book several times, this was the first time I heard the purportedly brilliant audio version read by the author. It was indeed brilliant. The book itself is indescribable, it’s a perfect mix of dry British comedy and insane science fiction.
  • Douglas Adams: “The Restaurant at the End of the Universe” (1980) book
    • The second book in the series, it’s much in the same vein as the first, continuing where it left off and bringing the same strange mix of sci-fi, suspense and humour. The sentient cow scene at the eponymous restaurant are the first I read from the series, in a primary school English class, discussing both comedy, sci-fi and the ethics of eating animals.
  • Douglas Adams: “Life, the Universe and Everything” (1982) book
    • The third book, it’s a step down to be honest. It’s still exciting and funny, but I think the large scope (stopping a galactic war) hinders the comedy a tad. Reading it was first written as a Doctor Who story and then later turned into a Hitchhiker novel makes a lot of sense, seeing as it’s much closer to Doctor Who (which focuses more on the action and has comedy second, opposite of Hitchhiker).
  • Douglas Adams: “So Long and Thanks for all the Fish” (1984) book
    • “So Long and Thanks for all the Fish” is again much closer to the original two novels, with a zanier and harder defined plotline than the somewhat straighter “Life, the Universe and Everything”. It’s filled with observational and absurd humour as well as finally reaching themes of love and friendship, previously relatively unexplored in the series. It is handled well, as is the character of Fenchurch, and the finale is brilliantly Douglasesque.

Främjandet av svensk rymdturism (motion till PP:s vårmöte)

Detta är en motion jag lämnat in till Piratpartiets vårmöte 2012. Dit och rösta och kommentera med dig.

Den 8 juli 2011 skedde den sista uppskjutningen med NASA:s rymdfärja, efter 30 år i drift, som ett ödets ironi nästan precis tio år efter att den första rymdturisten Dennis Tito for upp i rymden den 28 april 2001. Rymdturismen har år 2012 fortfarande inte börjat ordentligt, men andelen företag som satsar på branschen har stigit kraftigt det senaste decenniet. Richard Bransons Virgin Galactic blev 2011 det första kommersiella företaget i rymden, och planerar att 2013 eller 2014 genomföra de första turistresorna. Priset ligger på $200 000 US, bara en tiondel av vad Dennis Tito betalade för tio år sedan, och 500 miljonärer har redan skrivit på de första avtalen.

Sett till sin folkmängd är Sverige ett av världens ledande rymdnationer, och raketbasen Esrange i Kiruna har redan valts ut av Virgin Galactics som en av de mest intressanta platser att använda som europeisk bas. Esrange genomför sedan årtionden tillbaka världsledande astronomiska och geologiska undersökningar, och Kiruna är en utmärkt plats att utgå framtida rymdturism från, med redan etablerad professionell personal och en ovanligt god infrastruktur för en relativt isolerad stad. Detta är Sveriges chans att få vara med i början och utnyttja en helt ny bransch, som kan leda till en enorm mängd turism, förstärkt förtroende i astronomiska sammanhang, och en boom i Sveriges vetenskapliga utveckling.

Ingenting är dock säkrat, och ett annat alternativ är Skottland. Det är nu Sverige måste utnyttja det försprång vi har med en färdigbyggd rymdhamn i Kirunas Spaceport Sweden. Redan idag erbjuder de resor på höga höjder för att uppleva norrskenet, men om inte Sverige satsar på Spaceport Sweden finns en stor risk att vi hamnar efter och missar en enorm chans.

För att Sverige ska vara redo att ta hand om rymdturismen när den börjar måste arbetet starta redan nu, vilket snart tas upp i riksdagen med motion 2011/12:Ub323 “Nationell strategi för rymdturism”, som behandlas i april. Oavsett hur det går med denna motion behöver Piratpartiet ta en ställning för att försvara Sveriges plats i den kommande rymdturismbranschen, för att veta var vi står när vi kommer in i riksdagen. 2014, ett år vi har en chans att komma in i riksdagen, är också ett år då rymdturismen kan börja bli en viktig fråga för svensk turism och forskning.

Jag yrkar att…

  1. Piratpartiet ska se rymdturismen i Kiruna som en potentiellt viktig del av Sveriges framtida turism.
  2. Piratpartiet ska ta politisk ställning för att utveckla staden Kiruna med onejd inför den potentiella rymdturismen.

The Beautiful Cosmos: Jupiter and Io

When talking astronomy pictures, it’s difficult to say which pictures  are ”real” and which ones are not. A great deal is obviously just computer generated or hand drawn, but the ones I post as part of the Beautiful Cosmos blog series all have some degree of validity to them. The first problem that crops up is simply that as soon as you get a photo from some distance (from a good telescope or a probe) the light you catch is not just visible. Most astronomy pictures try to represent the many variations of colours that the human eye simply isn’t capable to capture or comprehend.

Jupiter and Io as captured by NASA's New Horizons probe in 2007. Click to embiggen.

A problem is that we can’t really estimate the exact colours of nebulae, supernovae and galaxies when they are basically impossible to see on close-up without… you know, dying. So the basic answer to how for example a nebula would look from just a couple of light years is… you wouldn’t see it. It’s surrounded by clouds of dust blocking vision and – again – killing you. The best the astronomers can do is a rough estimate.

When it comes to planets and moons, it’s a little different. Almost all pictures of moons (including our) and the planets (including Earth) that you’ll see, including ones I post, are composites of several different pictures, sometimes just a couple and sometimes several dozens. That doesn’t make it the less real, it just allows for much higher precision than if you took a photo of the entire planet at the same time. The end result is basically how it’d look in real life. To me, this is real enough.

A great deal of high-detail photos that include several objects (such as a planet and its moon(s)) are ”fake” in that they are composited of different pictures. All photos you have ever seen of several planets (close up) at the same time are totally fake. Planets simple aren’t close enough, and photographing two planets in our solar system together is akin to photographing two flies on opposite sides of a football field. Obviously it can be done – planets like Venus, Jupiter, Uranus and Mars can all be viewed simultaneously on Earth’s night sky – but they won’t be in such high detail.

This picture, of Jupiter and it’s moon Io, is both real and fake. It’s all real, but the Jupiter part is made up of three composites, and the Io part is taken at a different time and then added. Still, they seem to fit in proportion, and from the right angle this is just as awesome as it would look. Read more about the authenticity of this particular picture on the Bad Astronomer Phil Plait’s blog.

The Beautiful Cosmos: Aurora Borealis from Space pt. 2

My old post with a photo of aurora borealis as seen from the International Space Station (ISS) really is nothing in comparison with this new 30-second video. The ISS is filming from above Canada, with the awesome green light reflections shimmering beneath.

The Beautiful Cosmos: Rhea

The Cassini probe recently caught some new breath taking pictures of Saturn’s second largest moon Rhea, a beautiful astronomical body. Wow. I recently wrote about the beauty of our own moon, and it’s amazing to ponder about the countless number of similar bodies out there.

Click to embiggen.

NASA · Space Daily · Tom’s Astronomy Blog · Yahoo

China is taking over the space market

Tiangong-1, launched in September 2011.

China’s space programme has been increasing at incredible velocities in the past decade or so, and by all accounts it will continue to increase in the foreseeable future. They recently became number two concerning satellite launches, launching a total of 19 satellites in 2011, beating the US which launched a total of 18, but still behind Russia with 36 launches. As USA’s space program continue to drop both when it comes to budget and launches, China will likely stay in the very top, possible even beating Russia in the upcoming years.

The Chinese now estimate launching 30 satellites with 21 rockets in 2012, and staying at an average of 20 launches per year until 2015. At the same time, their Tiangong-1 space module was launched in 2011, hopefully to be followed up by larger Tiangong-2 and Tiangong-3 modules in the next few years. The real trials of Chinese manned space docking will start in 2012, and if successful the Tiangong programme will be in the size of the ISS within a decade.

The dragon is rising.

BBC (image source) · Space Daily

The Beautiful Cosmos: Jupiter

Jupiter has grown to become one of my absolute favourite planets in the last few months. Not sharing Mars’ potential for life, Saturn’s fantastic rings or Uranus unfortunate name, it’s often an overlooked planet, which is kind of a shame. It’s the biggest planet in the solar system, it’s mass being as much as two and a half times that of the rest of the planets combined. In other words, it’s freaking huge, and for that reason it’s also one of the most visible planets in the night sky throughout the year. Right now, it is clearly outmatched by Venus, and Mars is almost as bright, but throughout most of the year, when you look around and find a really bright spot… that’s Jupiter. If you get a small telescope and point to it, you’ll probably not only see the planet but also the four biggest of its dozens of moons – Io, Europa, Ganymede and Callisto. Europa is visible in the Cassini picture below (the dot in the lower left), and is definitely my favourite moon of the solar system, enough to warrant a future ”The Beautiful Cosmos” post.

The Beautiful Cosmos: Our Moon

The cosmos is fantastic. Such beauty lie in such basic features as the craters of our own gray moon, constantly hanging in the sky and freaking me out.

This picture may not look so different from many other fantastic Moon photos out there, not to mention the Chinese moon map I wrote about last month, but click it for a higher resolution (3886 x 4576) and you’ll see a fantastic view, a view to truly silence the heavens. The picture is a mosaic of 107 different pictures taken by André van der Hoeven. Support him, go buy the picture as a poster.

And yeah, I got the tip from Phil Plait’s blog. Follow it for more fantastic pictures, news and thoughts on astronomy.