Astronomy Down Under

2012

2009-11-27T02:11:07Z

Against my better judgment, I went to the theatre this week to watch 2012. My (short) comments below will include spoilers; if you intend to watch this movie and think that knowing some details about the plot will detract from the experience, skip the next three paragraphs (also... really? you'll watch this movie for the plot?).

In short: great CG, no plot. No need for a plot, one can argue. Sure, the movie does make a token attempt at explaining why is it that the Earth will be destroyed, but it felt a bit like that was tackled there after the catastrophes had already been decided on (major widespread earthquakes, California sliding into the Pacific, gigantic tsunamis) - the "weird neutrinos" explanation takes up some 30 seconds of a 151-minute movie, so you can guess how important it is to the story.

The odd things is that what really annoyed me about the movie is... John Cusack's family lives in Los Angeles, and he takes his kids camping in Yellowstone. That's a 1,700km drive. With two young kids in the car. No frakking way.

Other than that, if you ignore the carefully choreographed destruction scenes, the slow-motion collapsing buildings, the tsunamis showing up in deep waters and the continents moving over 1500 miles in one night, there are really not that many places to play the "scientifically inaccurate" card against the movie. Not that it is accurate (far from it), but if you're going to accept the main premise, you're in for everything else. As a colleague said: sit down, turn brain off, enjoy the effects.

Coming attractions - LCROSS

2009-10-06T03:11:35Z

This Friday (starting at 22:31 Melbourne daylight savings time, 11:31 UTC), a Centaur booster rocket will crash on the surface of the Moon, closely followed by the spacecraft it helped get there, LCROSS (Lunar Crater Observation and Sensing Satellite). This is expected to be a spectacular event that will create a plume of debris several kilometres high -- and was carefully planned.

The intention of this phase of the LCROSS mission is to look for water near the southern lunar pole, testing the hypothesis that water ice exists at the permanently dark bottom of polar craters. In order to do that, the booster rocket that carried LCROSS (and its cousin LRO) up to the Moon will be made to crash into the crater Cabeus. The resulting plume of debris will then be studied by hundreds of Earth-based observatories, the lunar orbiter LRO, the Hubble Space Telescope... and the LCROSS craft itself, which will fly through the plume, analysing its composition directly. It will then crash on the same crater, four minutes after the booster, generating another (smaller) plume which will be similarly studied from a distance.

One interesting thing to be aware of: the debris plume should be easily seen from the Earth with any moderately-sized telescope (minimum aperture of 10 to 12 inches) as it is illuminated by the Sun (the actual impact won't be visible as it will be hidden by the crater walls). Of course, for this you will need to be on the side of the Earth facing the Moon -- and this does not include Australia. The best place to be is the middle of the Pacific Ocean, in fact, but the west coast of the USA is well located as well (the east coast, as most of South America, will have the Moon on the sky but will also have the Sun).

For Melbourne, the Moon will rise at 1:07am the next day, at which time nothing should be visible (the plume will have long since fallen back onto the surface). The best way to watch the impact, then, will be through NASA TV. NASA has put together an excellent LCROSS viewer's guide which will tell you where to go (and, if you happen to be in one of the right locations, where to look at and how).

More information (much more, in fact) can be found at the main LCROSS mission page.

Coming Attractions - MESSENGER

2009-09-27T04:33:29Z

Several space missions will start to deliver new science data in the next weeks or months, and will certainly bring lots of new information about many different aspects of the universe. Let's start looking at them...

MESSENGER

The MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging) probe was launched in August 2004 and will start orbiting Mercury in 2011. It is taking a very complex route to get there: it has already flown by Earth in 2005, Venus in 2006 and 2007 and Mercury twice in 2008, yielding interesting science results on each of these passes. It is now about to make its third, and final, flyby of Mercury, using the planet's gravity once more to change its (the probe's) trajectory and lead it to an orbit insertion maneuvre in 18 March 2011.

The closest approach on this flyby, at 228km above the surface, will happen early in the morning of Wednesday, 30 September (7:55am Melbourne time); the image on the right (click to enlarge) is the view of Mercury from the probe last Friday, 25 September, at a distance of approximately 1.3 million km.

During the two previous flybys the probe mapped large areas of the surface that had never been seen properly. This time we will also get to see some small, still unmapped areas, but the main focus of the mission will be on getting better resolution images for some previously imaged areas and turning the probe's instruments on "interesting" areas identified earlier in the mission. Some of these include some unusually bright and some seemingly young craters; MESSENGER's website has a full description of these targets.

This flyby, like the previous two, will be packed with activity, as scientist try to squeeze as much information as possible from the few hours of close approach to the planet; nothing describes the frantic activities better than this panel provided by NASA, illustrating all observations that are planned in a graphical timeline. Also, for a full understanding of the complexity of MESSENGER's route from the Earth to Mercury, check out the Where is MESSENGER? webpage.

Astrophotography from home

2009-09-05T10:50:52Z

Just playing with my camera from home... this is what you can photograph in the sky from a very light-polluted place (central Melbourne) with a standard DSLR camera and no telescope (but a slightly long exposure):

Click on the image for a larger version. Io and Europa were visible through binoculars, but were lost on the glare of Jupiter on this photo. The dark band across the sky (in the large image) is a result of reflection on the window, as the photo was taken from indoors.

40 years ago...

2009-07-18T23:55:59Z

...Neil Armstrong, Buzz Aldrin and Michael Collins were inside the Apollo 11 spacecraft, on their way to the Moon. They would reach their destination on 21 July at 6:17:40 AEST (20 July 20:17:40 UTC), and Neil Armstrong would become the first human to set foot on the Moon a few hours later, at 12:56 AEST. Images of this event were sent to the whole world from tracking stations in eastern Australia, as anyone who's watched "The Dish" knows.

There is really not much I can write about this event that hasn't been written before and better by other writers, so I will simply let this post mark the occasion. Or, rather, I will let the image below mark the occasion.

That is the Apollo 11 landing site, as photographed last week by the NASA Lunar Reconnaissance Orbiter, current on its mission orbiting our satellite. You can clearly see the Eagle landing module, and if you click on the image you'll be taken to the NASA article with images of the landing sites of the other Apollo missions. And the best thing is: better images will come. These pictures were taken before the LRO reached its final orbit, and future passes over these sites will yield much better resolution.

So, let's celebrate the past with an eye on the future. Here's to our return to the Moon!

Forty years ago today...

2009-05-18T06:46:21Z

On 18 May 1969, Apollo 10 was launched from the Kennedy Space Center in Florida, the last mission in preparation for the Moon landing mission that was to come three months later.

Apollo 10 was a full "dress rehearsal", the only one in the Apollo program. The ship was identical to the one used for Apollo 11, and everything progressed — on board and on land — just as if a landing was going to happen. The Lunar Module was deployed on 23 May with Thomas P. Stafford and Eugene A. Cernan on board, leaving John W. Young alone in the command module, and it descended towards the Moon, spending six hours away from the Command Module and getting as close as 15.7km from the surface before going back up and docking.

The mission landed safely on 26 May on the Pacific Ocean, some 500km east of the American Samoa islands, and after that NASA was ready for the "real deal" with Apollo 11.

Commander Thomas Stafford left NASA soon after (ostensibly due to not having been selected to fly Apollo 13) and never returned to space; Young landed on the Moon with Apollo 16 in 1972 and flew the Space Shuttle's inaugural mission in 1981, among other missions; and Cernan has the distinction of being so far the last person to have been on the surface of the Moon, as a crew member on Apollo 17.

Launches

2009-05-10T09:58:58Z

This week will see, finally, the launch of space shuttle Atlantis carrying the astronauts for STS-125, the final Hubble servicing mission. This mission was delayed after Hubble developed some new faults late last year, but it looks like this time everything is going to happen as expected. As I write this, the countdown stands at 1 day, 8 hours, putting the launch in the early hours of this Tuesday, Melbourne time. At the same time, space shuttle Endeavour also sits on the launch pad, ready to act as Atlantis' rescue ship should anything go seriously wrong while in orbit.

But this week will also see two other important launches, neither of which is getting as much attention as it deserves. On 14 May at 23:12 Melbourne time (13:12 UTC), an Ariane 5 rocket will be launched from the Guiana Space Centre carrying two European observatories into orbit:

the Herschel Space Observatory is a 3.5 metre telescope, the largest space telescope ever launched; it will look at the universe in the low energy range of the far infrared, looking at what its creators call "the cool universe" — objects that are either not hot enough to emit visible light or far enough that their light is shifted into the far infrared by the time it gets to use
the Planck observatory is a microwave telescope that will look into the light emitted by the Big Bang, investigating variations in the temperature of the background radiation that permeates the universe; it intends to look at the Cosmig Microwave Background with a level of detail never before achieved and to bring us new insights into the properties of our universe during its early years

Both Herschel and Planck will be far away from the Earth, orbiting around L2 (the second Lagrangian point); this puts them around 1.5 million kilometres away and permanently in our night side. This allows both to operate without any interference from Earth's radiation belts and reduces the area of sky that is "off limits" to their instruments (since both the Earth and the Sun will be in the same general area of sky from the point of view of the observatories).

Hubble has certainly given us and our scientist an amazing amount of information about the universe over the years, and I do hope this servicing mission goes according to plan. But let's also hope that Herschel and Planck lift off without problems and bring us much more information over the next few years.

Carnivals...

2009-04-14T10:53:46Z

I missed on posting about it, but the Carnival of Space keeps on going, and we're getting closer and closer to the 100th edition!

The latest one, #98, is up at Universe Today, and #97 is at Cheap Astronomy. Universe Today also has an archive of all 98 editions so far, so you all can spend a few (or many) hours reading the best of the astrosphere. Enjoy!

The growth of the ISS

2009-03-31T10:50:08Z

Space Shuttle mission STS-119 has just landed back in Florida, after delivering the latest addition to the International Space Station. I thought this would be a good time to look at how the station grew over the years.

In November 1998, this is what the ISS looked like. That's the control module Zarya (Russian for "dawn"), which was launched by Russia and was the first piece of the ISS to reach orbit. It was, indeed, fairly small: only 13 metres long from end to end (the solar panels span a bit under 25 metres). It was joined a few weeks later by module Unity, carried to orbit by Endeavour.

By 2002, the station had grown considerably. It retained basically this shape for several years, and I guess that's the shape many people think of when they think of the ISS — "lopsided", with solar panels only at one end.

And this is what it looks like now, after the recent mission; it is now 73 metres long and 104 metres wide, with the solar panels fully extended. It is still not complete, though: there are four more assembly missions in the schedule, two by NASA's space shuttles and two by Russian crafts. Assembly won't be completed until late 2011, at the earliest.

Still, with its very large (and reflective) solar panels, the ISS is already the brightest object visible in the sky (with the exception of the Sun and the Moon, of course) and can easily be seen from the ground if you know where (and when) to look; I recommend using the website Heavens Above for that. With a reasonable telescope and on a good day, you should be able to see the shape of the station in detail, but even small binoculars should allow you to see that it's a large object (and not simply a point of light).

(and for anyone interested, NASA has a much larger sequence of pictures showing the assembly of the station; they don't yet include the results of the latest mission, though)

Victorian bushfires

2009-02-10T03:48:24Z

With the events of the last few days in Victoria, this is certainly a time to stop looking up for a while and look around us. There has been an unbelievable level of suffering caused by the loss of life and property, and even those of us not directly affected by the fires feel completely dazed by the magnitude of what happened. In fact, it would seem most Victorians know someone — friend, family, colleague, friend-of-friend etc. — who has been touched by the events.

If you are in any condition to help, Red Cross Australia has set up a fund to assist individuals and communities affected by the fires; you can donate at their website. The RSPCA is coordinating efforts to provide assistance to the animals — both pets and wildlife — affected, including reuniting lost pets with their families; they accept donations (money, supplies or pet food) and also volunteers, so head to their website if you can help. Also, Coles supermarkets will be donating all their proceedings next Friday to the relief efforts; I expect more companies will be announcing similar measures in the near future.

Any help will make a difference.

Penumbral eclipse of the moon, tonight

2009-02-09T04:32:02Z

Most people won't notice it, but we will have a lunar eclipse tonight, visible from anywhere in Australia (weather permitting, of course) — and also from New Zealand, most of the Pacific, Alaska, China, parts of India and most of Russia. The continental US sees only part of the eclipse, with the Moon setting before it ends.

A penumbral eclipse happens when the Moon goes through the penumbra of the Earth, the area of "partial shadow" around the main shadow of the planet. Viewed from the Moon, this appears as a partial solar eclipse (an umbral eclipse is seen from the Moon as a total solar eclipse).

In eastern Australia, the eclipse starts at 23:36 ~~AEST~~ AEDT (12:36 UTC), with the maximum eclipse at 01:38 tomorrow morning (14:38 UTC). Visually, you will see one "corner" of the full Moon clearly darker that the rest of the disk. More information and a visibility diagram can be seen at the HMNAO eclipse's website.

Carnivalia

2009-02-08T02:33:41Z

It's been a while since I remembered to link to the Carnival of Space... this week's edition, Carnival of Space #89, is now up at The Moon Society, and it's the special lunar edition! (with plenty of links about other celestial objects as well, including the Earth)

Last week's edition, #88, was at TheSpacewriter's Ramblings, and it's loaded with links — it seems to be a particularly long edition, so make sure you explore it adequately. It even dips into scepticism, with two entries helping fight the waves of woo that continuously hit our shores.

Good reading!

Australia Day Eclipse

2009-01-19T05:23:13Z

Next Monday (26 January) is Australia Day, and nature will help in the celebrations with a partial solar eclipse visible from the whole country (except Tasmania) — even if barely, from some places.

This is actually going to be an annular eclipse in some parts of the world, most of them covered by water. The path of the eclipse starts over the South Atlantic, southwest of South Africa, and follows east from there over the Indic Ocean ending over Indonesia, which is the most significant land mass from where the annular eclipse will be visible.

In Australia, the places with the best view will be (not surprisingly) those closest to Indonesia. Darwin will see the Moon covering a bit less than half of the Sun (41.3%, to be precise), with the maximum occultation happening just before sunset, at 7.03pm local time (the sun will set during the eclipse). From Melbourne, we'll see the Moon covering just about 0.4% of the Sun at 7.54pm local time — just a barely visible "nick" on the Sun's disk, but it should still be visible (the sun sets at 8.38pm on that day). Sydney sees 1% of the Sun being covered at 7.59pm, which is just about at sunset.

The weather forecast for next Monday in Melbourne is for a sunny, cool day, so going out to look at the sunset and to try to spot the eclipse might be a good program for the end of the holiday (just remember to be very careful when looking straight at the Sun).

Methane on Mars

2009-01-16T11:01:05Z

NASA has announced yesterday the discovery of methane in the Martian atmosphere, and that has become huge news quite rapidly; I've even seen it mentioned on TV earlier today.

Why is that an important discovery? Well, methane is a very fragile substance; not only UV rays destroy it quickly (by breaking the atomic bonds), but so do exposure to oxygen or hydrogen peroxide. Mars lacks an ozone layer, so UV rays are very abundant there, and oxygen and hydrogen peroxide are not that hard to find either. Taking all that into account, the fact that there is any methane at all in the atmosphere means that it is being created and released by some process.

On Earth, most processes that release methane are biological. Bacteria release large amounts of it while processing organic matter, and so does cattle (technically, the bacteria in their guts). We know there is no cattle in Mars, but we can't rule out underground bacteria.

There are geological processes that can release methane as well; however, it is (was?) thought that Mars is pretty much dead, geologically speaking. So, this discovery means that either there are some previously unknown geological processes going own in the red planet, or there are biological processes. Both possibilities are very exciting, but it will take a while before this can be settled.

Mars keeps surprising us, and I don't think it will stop any time soon!

IYA2009 goes for gold

2009-01-07T02:59:10Z

The Royal Australian Mint is taking part in the celebrations of the International Year of Astronomy with two commemorative coins issued in 2009: the one dollar coin (pictured) features the Parkes radio telescope (about which I wrote here) and the twenty cent coin is themed around community involvement with astronomy, showing stargazers looking at the starry sky.

I don't think the coins are in circulation yet, but some commemorative sets (such as this) are for sale at the Mint's online store (and in the physical store in Canberra as well, I assume).

(thanks to arthwollipot, who mentioned this in the JREF forums)