Saturday, June 30, 2007
Venus and Saturn together!
The dance of the planets climaxes tonight and tomorrow night (June 30th, July 1st) when Venus and Saturn are at their closest. Of course, most of southern Australia and the eastern seaboard are under cloud, or being flooded, or just recovering from floods, so viewing this event may not be easy.
Still, do make an effort, this is a fairly rare and attractive event. The best times to look are between 6:00 pm and 8:00 pm (your local time), Venus will be very easy to recognise, being the brightest object in the north -west sky, Saturn will be the dimmer object only about a fingerwidth away. In a small telescope you can see both Saturn and Venus together in a lowpower objective. This will be very nice.
Also, tonight (Saturday June 30th) is a Blue Moon.
Extreme Solar Systems
Friday, June 29, 2007
The ninth Carnival of Space is now up!
Labels: carnival of space
Thursday, June 28, 2007
The ABC's war on Science
...in the ABC's recently revised editorial policies, a priority is placed in allowing principal relevant viewpoints on matters of public importance to be aired. We want the ABC to be Australia's town square where people can debate, hear alternative views and learn from each other.Sorry Kim, the sad fact is that the alleged documentary is not a contribution to a debate, but complete rubbish. It gets the basic facts of climate change wrong, it ergeriously quotes the lone climate scientist out of context (the majority of its so called climate experts are nothing of the sort), and it uses, to not put too fine a point on it, made up data* to make it appear as if climate hasn't changed (and their graph of solar activity vs temperatures is a little, shall we say, imaginative and shows a spurious correlation due to arithmetical errors). And its not like these basic flaws weren't well known when Aunty purchased this piece of fiction.
It was in that spirit that ABC television made the decision to purchase the year's most contentious documentary, The Great Global Warming Swindle, written and directed by British producer Martin Durkin.
What's next Aunty? "The Great Heliocentric Swindle" complete with faked data showing the Sun orbiting the Earth?
UPDATE: To be fair to the actual Science Unit of Aunty, the TV management ignored the advice of the Robin Williams of the Science Unit, whom I have the greatest resect for.
*Yeah, there could have been an honest mistake where the vertical scale was exagerated, and 1988 was removed from the graph and replaced with 2000, without adding in the data to 2000 (see this image here comparing their graph to the real data) and then this mindboggling bit of incompetence had to be missed during the fact checking and post production of the show. This graph was a key part of their "argument", and if they can't get that basic fact right, with all the publically available data out their, it speaks volumes about the "accuracy" of the rest of the show.
Wednesday, June 27, 2007
What will etxrasolar planetary atmospheres be like?
The giant outer planets have atmospheres very similar to the composition of the primordial solar nebula, as the larger mass worlds could hold onto more of the primordial atmosphere.
For exoplanets, we expect similar relationships to hold. Large, Jovian style worlds should have atmospheres very similar to Jupiter or Saturn for example. However, in many extrasolar systems the worlds have migrated inwards to much hotter regions, so their atmospheres will probably have evolved to some degree from that of Jupiter. Hot super Jupiters like HD 149026b are very dark, as dark as charcoal, suggesting their atmosphers are no longer Jupiter standard .
To give an idea of how this may affect a world, lets take the super-earth Gliese 58 c. Just to refresh your memory, Gliese 581 C is a 1.5 Earth radii planet that was originally thought to be in the habitable zone of its host star, but outside the orbit of a "hot Jupiter" Gliese 581b. The history of Gliese 581c's formation will be critical to its atmospheric composition. If Gliese 581c was formed from the debris of a terrestrial-like world shattered when Gliese 581b migrated to its present star hugging location (see Mandell 2007), Gliese 581c would have lost most of its original atmosphere, and had to develop a new one from out gassing of volatiles in the rocks that formed it. So if Gliese 581c is a terrestrial world, then it could have a predominantly CO2 atmosphere. How dense is a good question, as we still don't have a clear idea of the original atmosphere s of Earth, Venus or Mars when they formed, anywhere between between 1 Bar and 20 Bars (where 1 Bar is the atmospheric pressure of current Earth, Venus is around roughly 90 Bar).
So while we have a fairly good idea of what an exoplanetary atmosphere may be like, the evolution of these worlds atmospheres may be far from simple, and surprises may wait us when we finally get in a position to look at the m in some detail.
Formation of Earth-like Planets During and After Giant Planet Migration Mandell AM et al. The Astrophysical Journal, volume 660, part 1 (2007), pages 823–844
More Meteor Poetry
-by Andrei Dorian Gheorghe (Romania)-
I think that a fireball
simulated in a planetarium
is like a robot
wishing to be a man,
or rather like a firework
wishing to be a real star.
For the rest of the poems, and back issues, follow this link. More meteor poetry is at Astropoetica and Cosmopoetry.
Tuesday, June 26, 2007
Blue Moon This Saturday
If you want to sing the "Blue Moon" song on saturday night, here are the lyrics (along with a range of other Moon songs).
Sunday, June 24, 2007
Veuns an Saturn meet in the evening.
The almost final act of the Venus - Saturn hi-jinks occurs this week. Venus and Saturn rapidly draw closer, by Saturday 30 June and Sunday 1 July they will be less than a fingewidth apart. If you have a small telescope, you can see the ringed world and the crescent Venus in the same low power eyepiece field.
Venus is the exceedingly obvious very bright planet above the north-western horizon. The best time to observe is between 5:45 and 7:30 pm. This will be very attractive to watch over the coming nights.
Friday, June 22, 2007
*despite all the rain, and the savage storms lashing the east coast, our resivours and rivers are still periolously dry.
The 8th Carnival of Space is now live
Labels: carnival of space
Thursday, June 21, 2007
Another Moon and Venus Shot
Wednesday, June 20, 2007
Comet 2007 M1 McNaught
Tuesday, June 19, 2007
Heavy Metal on Titan
Venus, Saturn, Regulus and the Moon
Tonight, with Saturn just above the Moon, was especially beautiful. I got out the 4" scope and had a look. Ringed Saturn floating above the craters of the Moon was very nice indeed.
Tomorrow, The Moon is near Regulus, andother attractive lineup, well worth a look.
More Venus in Daylight
Yep, this is the real deal. Taken 15 minutes before sunset, no clouds hiding the Sun, which was visible through the trees when I moved around setting up the shot. Unlike yesterdays image, which was on the threshold of sunset.
Several of my colleagues were leaving for home and wandered up to see why I was taking photos of empty sky. So I held an impromptu "footpath astronomy" session and I pointed out Venus to them and explaine dthe significance of this. Most people were impressed that they could see a planet in daylight.
I also went out at around 3;00 pm as well, after a few minutes looking in the wrong spot, I realised Venus was higher and spotted it instantly. I'm getting my eye back in for Venus in the daytime (I used to be very good at spotting it, but this year has been very hard to pick it out).
Over at SpaceWeather, they have a gallery of images from the occultation of Venus, take a look.
Monday, June 18, 2007
Daytime Venus again
Venus in the daytime, just. This image was taken about 2 minutes before Sunset, with the Sun behind a heavy bank of cloud. So it just squeaks in as "daylight". Venus is the dot near the top right hand corner (click to enlarge).
Today alternated between fantastic blue sky and pouring rain. Of course, we would have a fire alarm-induced evacuation just when it was pouring hardest as well (and me without my raincoat).
About 3:00 pm it was clear again. I walked around the main building so that I could have a clear view north, but with the Sun blocked by the main building. Withing a few moments I could see the Moon, and then Venus was visible, clear as a bell. It was also close to the car park building, so I had a handy referent. I took a couple of pictures, but you really can't see anything in them, even the moon is a pale blur.
I went back to get the students, but it started raining again. Later, it did clear up and I was able to show them Venus, and they thought that was cool. I managed to get some shots on the way home (the above image for example), then the rain closed in again.
Blast! I missed the Moon Bounce
Sunday, June 17, 2007
All Hail Eris, Queen of the Dwarf planets
Remember Eris? The icy worldlet that was bigger than Pluto? The one, that when it was proposed that it become the 10th planet an astronomical brouhaha resulted with Pluto demoted to being a Dwarf Planet? Well, it now turns out that Eris is heavier than Pluto as well. By observing the orbit of Eris's moon Dysnomia, Mike Brown and his team were able to determine the mass of Eris. It turns out to be around 27% heavier, than Pluto, which suggests that Eris and Pluto are of similar composition, mostly ice with some rock thrown in. You can read more about this at Science, Nature, New Scientist, ABC science Online and Centauri Dreams.
Poetry to the Moon and Back.
Seeing Venus in the Daylight
Venus is currently bright enough to see in the daylight. However, as it is a tiny dot in the vast expanse of sky, finding it can be difficult. If the Moon is nearby, you can use it as your guide to find Venus.
On Monday 18 June the 12% illuminated thin crescent Moon will be just a handspan from Venus. So to find Venus, first locate the Moon, then look a handspan to the right and slightly up form the Moon. The Moon itself will be relatively difficult to see unaided, but at 3:00 pm on Monday it will be almost due north and between 5 to 6 handspans above the northern horizon (see the diagram above). Once you find the Moon, Venus will be very easy to find nearby. You can of course view at other times, but the 3:00 pm time gives a better guide to the Moon.
As this is a daytime observation be VERY careful of the Sun, do NOT look directly at the Sun. It is 7 handspans away from the Moon, but care is still needed. Make sure a building, wall or tree is blocking out the Sun before attempting viewing. This improves safety, and improves your ability to see Venus and the Moon as well. If using binoculars ALWAYS make sure you are pointing them a away from the Sun, exercise extreme caution, as you can lose your eyesight if you accidentally look at the Sun through binoculars.
In other parts of the world they will see a daytime occulation of Venus, there will be an attempt to webcast this event (tip of the hat to daveP). More details at the Society for Popular Astronomy.
Saturday, June 16, 2007
Venus and Saturn Hi-jinks
Over the next week we will have something to keep us entertained in the evenings. A dance of the planets with Venus and Saturn.
Venus can be readily seen as the startlingly bright object in the northwestern evening sky between sunset and around 8:00 pm. Venus is in a line with Saturn and Regulus, the brightest star in Leo, which are also in the north-western sky above Venus.
Venus draws closer to Saturn over the week. By Sunday the 17th, Venus, Saturn and Regulus are equidistant. On the 19th-21st the crescent Moon joins the line-up, sitting just below Saturn on Wednesday the 20th. This will be a very attractive sight in the evening, and well worth a bit of astrophotography.
Friday, June 15, 2007
Globe at Night analysis in
Thursday, June 14, 2007
The 7th Carnival of Space is now up
Wednesday, June 13, 2007
So is Gliese 581 c really a Venus like inferno?
Remember Gliese 581c, the 1.5 Earth radii, 5 Earth mass planet that caused so much excitement? It was reported to orbit within the red dwarf Gliese 581’s Habitable Zone, making it the most Earth-like world yet found. The Habitable Zone of a star can be broadly defined as the zone where liquid water could exist on the surface of a planet. There is a lot more to habitability than just liquid water, but bear with me for a moment.
It is however obvious that the actual surface temperature of the planet very much depends on the highly uncertain composition and thickness of its atmosphere, which govern both the planetary albedo and the strength of the greenhouse effect. It is probable that the planet is located towards the “warm” edge of the habitable zone around the star
Tuesday, June 12, 2007
Venus, the Beehive, and the celestial hockey stick
Venus was on the edge of the Beehive cluster tonight, tomorrow night it is in the heart of the beehive. An attractive sight, but best viewed with binoculars.
As well, while you are out looking at Venus in the Beehive, there is a farily broad but interesting line up of bright stars and planets. Sirius, Procyon and Venus are in roughly a straight line, forming the handle of the hockey stick. Up to the right, Saturn and Regulus form the blade. Okay so it's not the Pleiades, but it is an nice formation. Also, while looking at Venus, turn around 180 degress, se that bright object, that is Jupiter. Jupiter and Venus are now alomst directly opposite each other, making the evening sky a very nice sight indeed.
Just goes to show what happens when you aren't paying attention, back on Friday 8 June, about when we were heading for Naracoorte, a sun grazer comet headed in for a close pass to the Sun ... and didn't make it back out. There is an animation here (1 Mb). CometAl also has a nice composite image from SECCHI/STEREO in his gallery.
Monday, June 11, 2007
Just one of those weekends
So of course it was couldy. First night out, I actually got to see an Iridium Flare through the clouds, pretty neat, but cloudy as all get out otherwise. Next night was clare while we were having tea, and playing table tennis with the younglings. It was clare as I set my telescope up. No sooner had I got Jupiter in my sights then "whoosh" cloud. Driving home the sky was clear, and we could see Venus beconing as we drove into Adelaide. Now, cloud.
At least we did some caving and saw some fantastic fossils to make up for the cloud. And lost of bushwalking.
Friday, June 08, 2007
Grazing occulation movie
Here's Dave's comment:
Rodney's movie of the Lunar Graze of ZC 1459, with sound for the first 3 events. MovieMaker would not let me get the sound in sync exactly. However, the reported times we obtained are accurate for all events.
Venus and the Beehive, Vesta and Mars.
Keep your eye on Venus over the next few days. Venus is now reasonably high in the evening sky, and visible after astronomical twilight. Between now nad August Venus will unbdergo a series of rather beautiful encounters, so its worth watching Venus for some time.
The first notable meeting is Venus and the Beehive cluster. This delicate little cluster lies in the heart of Cancer, the crab. AT the moment, Venus is around a handspan from the Beehive, obver the next few days it will move closer, and between the 11th and 14th Venus will be in the same binocular field as the Beehive. The will be at their clsoest on the 13th, as shown in the image above. The beehive is dim, so you will probaly need binoculars to see this encounter at its best. Following this, Venus meets Saturn and Regulus so keep your eye on the bright planet.
If you are up early in the morning on Monday June 11, Mars and the cresent Moon are close together.
The asteroid Vesta is at magnitude 5.5, and can still be seen with the unaided eye in dark sky sites. A printable lcoation map is here.
Thursday, June 07, 2007
Speaking of Transits
No transits for Gliese 581
So, the results while disappointing in that we miss out on finding more about Gliese 581c (or d), but we know a lot of interesting information about the system. I'll blog some of my ideas about this later on. Centauri Dreams also has some good discussion of this report.The MOST results ... rule out dips in the starlight down to a level of about 0.1%that would be caused by a transiting planet roughly the size of theEarth. That doesn't mean there's no planet, just that from Earth, wedon't see its orbit nearly edge-on. But it does mean we can't directlymeasure the size of the planet Gliese 581c, to test models of itsstructure. That's the disappointing news.The encouraging news is that the star itself seems remarkably stableover the six weeks it was monitored by MOST. The brightness of the starchanged by only a few tenths of a percent over that time. This level ofstability means that this red dwarf star provides a stable source oflight, hence heat, to the surface of planet Gliese 581c. "The climatethere should not be a wild rollercoaster ride that would make itdifficult for life to get a foothold," notes MOST Mission Scientist Dr.Jaymie Matthews, a professor in the Department of Physics & Astronomyat the University of British Columbia. "It also suggests the star isquite old, and settled in its ways, so that the planets around it havebeen around for billions of years. We know it took about three and ahalf billion years for life on Earth to reach the level of complexitythat we call human, so it's more encouraging for the prospects ofcomplex life on any planet around Gliese 581 if it's been around forat least as long."
Tuesday, June 05, 2007
It's ASMR Medical Research Week!
June Southern Skywatch Now Up!
Anyway, the June edition of Southern Skywatch is now out. Yes, its late, marking, end of semester guff, kiddy illnesses and all that. Sorry folks.
As well as the opposition of Jupiter, there are more maps for unaided eye Vesta, Venus and Saturn dancing together, and a blue Moon.
Sunday, June 03, 2007
Sunspot 960 putting on a show
Since last writing, Sunspot 960 has let off two more serious flares (and a host of minor ones), including a powerful M7.4 flare. You can see the details of that flare here, and here is some of the STEREO imagery of that flare.
It may be likely that Sunspot 960 will be visible with safe solar projection techniques. It is also becoming more likely, given its activity and the complex beta-gamma magnetic field, that Sunspot 960 could generate aurora.
Venus, Castor and Pollux
The weather here has been good for the fmares and dams, which means I have had virtually no chance to see anything. I got this shot of Venus and Gemini in between two bands of cloud and pouring rain. Heck the whole thing clouded over while I was taking the dark frame.
But I still got to see it, and it was awesome.
Friday, June 01, 2007
And so the week ends
Surface images of Altair
Other stars, such as Vega, Alderamin, and Betelgeuse have been mapped before (I didn't know that), but this is the first time a main sequence star has been mapped.
Sun flares again
The Sun just blasted out a M1.1 and C9.8 flare today. It's probably not from Sunspot group 958, the prominent group on the left hand side, but something sneaking up over the horizon (image courtesy of Space Weather).
If the spot keeps up its activity, we might get some geomagnetic action, perhaps even an aurora.
UPDATE: The Sun just let off two more M-class flares. Last time this happend though, the spot went quite soon as it moved into a position where it could produce aurora.