AMATEUR ASTRONOMY:

MOON, MARS AND ANTARES AT DUSK:

Early evening tonight 9too late) and tomorrow is a good time to spot an interesting triplet in the dusk sky towards the southwest. on these nights Mars and the Moon pair with the red supergiant Antares shortly after sunset. Antares is the brightest star in the constellation Scorpio and is so large that if it were in our solar system it would extend to somewhere between the orbits of Mars and Jupiter. it is about 600 light years from us, and has the visual luminosity of about 10,000 suns. Despite this its distance means that it is "only" the 16th brightest visual star. catch this triplet tomorrow evening (see diagram). look for Mercury as well.

AMATEUR ASTRONOMY:

TRIPLE CONJUNCTION THIS EVENING:

Yesterday the planet Mercury reached its greatest elongation , 27 degrees,(its highest above the horizon), but today it is still quite visible in the evening twilight. During the past week Mercury has formed a triangle in the evening sky with the planets Venus and Mars, and tonight Venus and mars make their closest approach, being only 18 arc-minutes from each other. Venus, shining at a magnitude of -3.9, will be the brightest of the trio, Mercury will have a magnitude of -0.2 and Mars, the dimmest of the pair, will shine at about 1.7. The diagram to the left shows how the planets will be on a line of sight this evening.

Mars will be located just slightly left of and below Venus, and Mercury will be below the air and to the left. The bright star Spica will also be visible further to the left. You will need binoculars or a moderate power telescope to view the trio because of the closeness of Mars and Venus and because of the interference of twilight. People living further south than Canada will have a better chance of viewing as the planets will appear higher above the horizon to them. Conditions are likely to be overcast here in Winnipeg, but people elsewhere may have better luck.

Good viewing.

AMATEUR ASTRONOMY:

WHAT WAS EARLY MARS LIKE?:

Evidence is accumulating that the planet Mars was quite wet in its early life. does this means that it once was home to life ? Here's an article from Space.Com about the latest findings about water on early Mars.

........................

Early Mars Was All Wet

By Andrea Thompson

A lot more Martian rocks were altered by water than scientists originally thought, suggesting that early Mars was a very wet place.

New observations made by NASA's Mars Reconnaissance Orbiter (MRO), currently circling the planet, have revealed evidence that vast regions of the southern highlands of Mars were altered by water in a variety of environments billions of years ago.

Water is a key condition for life as we know it. Though there is no firm evidence that Mars has ever harbored life, knowing that the planet was once wet suggests that it was at least habitable in the past.

The key to the finding is the discovery that rocks called phyllosilicates are widespread on at least the planet's southern hemisphere. The water present on Mars from about 4.6 billion to 3.8 billion years ago transformed some rocks into these phyllosilicates, which include clays rich in iron, magnesium or aluminum, mica, and kaolinite (an ingredient in Kaopectate).

"In a phyllosilicate, the atoms are stacked up into layers, and all of the phyllosilicates have some sort of water or hydroxyl [oxygen and hydrogen group] incorporated into the crystal structure," said study team member Scott Murchie of Johns Hopkins University.

Previous data from an instrument called OMEGA - Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activite on the Mars Express spacecraft had revealed only a few large outcrops of phyllosilicates, suggesting they were a relative rarity on Mars.

"It sort of gave the false impression that rocks that were altered like this were more restricted than they really are," Murchie said.

But the new observations, made with MRO's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and detailed in the July 17 issue of the journal Nature, reveal "thousands and thousands of outcrops that we can now resolve with the higher resolution of the instrument, and they're scattered all over the planet wherever the older rocks occur," Murchie told SPACE.com.

"What that's suggesting to us is that we're seeing a pervasive subsurface layer that goes back in time — it's been altered by water to clays and related minerals, and it's outcropping all over the place," Murchie added.

The layer of water-altered rocks sits below younger, volcanic rocks and the ubiquitous windblown Martian dust and sand in many places. But in craters and scarps, including Valles Marineris, across the terrain of the southern hemisphere, the ancient clays and other minerals have been exposed.

"It's like going to the bottom rock layer in the Grand Canyon," Murchie said, where ancient layers underlie the whole area, but are only exposed in a few places.

This layering gives scientists a dividing line of about 3.7 to 3.5 billion years ago for a transition in Martian geology: "Before that the rocks were altered into clays, since then they're not," Murchie said.

The variety of clays and other minerals formed also tells scientists that rock was altered by water under a variety of conditions.

"There's a variety of environments that are formed where the rock was lightly altered where you see things like chlorite, to where it was altered with water at really high temperature, where you see mica, to where a lot of water must have flowed through the rock in order to dissolve out the iron and magnesium and you're left with kaolinite," Murchie said.

The alteration of later rocks, such as the sulfates found by the Mars Exploration Rovers (MER), Spirit and Opportunity in the northern hemisphere, on the other hand, formed under much more restricted conditions.

One implication of these findings is that some of the environments that formed the phyllosilicates would not have been antagonistic to any potential life, unlike the conditions that formed the sulfates, which formed in a highly acidic environment similar to battery acid, as Murchie put it.

Whether the MER rovers can get a close-up peek at these phyllosilicates while the robots still roam the Martian surface is uncertain, Murchie said, because so far the rocks haven't been detected near the crafts. But they could be there and simply be obscured in the north from the MRO instruments by dust.

"It doesn't take much to hide something from our optical instrument in orbit," he said, just a few micrometers of dust. "So just brushing away the rock surface could be enough," he added.
Whether or not Spirit and Opportunity get a chance to investigate these intriguing rocks up close, future rover missions, such as the Mars Science Laboratory set to launch 2009, could certainly be aimed at known phyllosilicate-rich sites, Murchie said, shedding more light on the mysteries of early Mars.
Video Player: Mars Reconnaissance Orbiter
Get to Know MRO: Top 10 Facts About NASA's Mars Reconnaissance Orbiter
Zoom In: Water on Mars??

AMATEUR ASTRONOMY:

GEMINID METEOR SHOWER TONIGHT AND TOMORROW NIGHT:

The Geminid meteor shower, which usually peaks each year between December 12th and December 14th, is the most reliable and spectacular of the annual meteor showers even though observation is less comfortable than that of other showers such as the summer Perseids. On the other hand the skies are usually clearer in winter than at other times of the year. This year the predicted peak will occur at 16:45 GMT on December 14th. This is 10:45 here in Winnipeg in the CST zone. Consult the Time and Date.Com website for the equivalent time in your locality. Time and Date also gives the times of Sunrise/sunset and Moonrise/Moonset as well as a weather forecast. This year the Moon will not interfere with viewing as it is a thin waxing crescent that sets at 8:18 pm. The expected peak time will unfortunately occur during daylight, but a large number of meteors are likely to be visible tonight, especially in the early morning hours, or tomorrow night. The Geminids have a rather extended peak so that viewing doesn't depend on getting an exact time. All weather reports, whether from Time and Date, from Environment Canada or from the Clear Dark Sky website, indicate good clear viewing conditions tonight but overcast tomorrow night. The Clear Dark Sky site has a wealth of other useful information as to viewing conditions for a vast number of locations in North America.

The Geminids are a rather recent meteor shower, having first been observed by astronomers R.P. Greg, B.V Marsh and A.C. Twining first observed them. They were observed again in 1863 by A.A. Herschel. It was only during the 1870s that astronomers realized that a new annual shower was underway. The Geminids gradually increased in intensity during the last century. This year there may be as many as 120 meteors visible per hour near the peak period. Intensity will decrease only slightly from 6 to 1o hours on either side of the peak. The intensity increases gradually in the 2 to 3 days prior to the peak and then falls off rapidly. Thus tonight should be a good time for viewing, specially after 2:00 am when Gemini is high in the sky (the number of meteors visible is largest when their radiant approaches the zenith).

The meteors of the Geminids are of medium speed, approaching Earth at about 35 kilometers per second. They are bright and usually white in colour, and are often productive of some spectacular fireballs. Their apparent speed is slow, and they can sometimes been seen to have jagged paths and to seemingly split. They leave few visible trails however. The radiant will come from a point just to the northwest of Castor, the upper star in the constellation (see diagram above). The Geminids are rather unique in that they originate from an earth-crossing asteroid, 3200 Phaeton, unlike other meteor showers which originate from cometary debris. This parent body was discovered as recently as 1983 by S. Green and J.K. Davies, using the Infrared Astronomical Satellite. This year Phaeton will be making its closest approach since 1983, coming within 11 million miles of Earth. There is some dispute about the nature of Phaeton as some believe that it is not an asteroid but rather the burnt-out nucleus of a comet.

So look to the northeast early this evening, and higher in the sky later to find Gemini, and happy frigid viewing. Have a look out for Mars as well. It shines brightly at the right-hand side of Gemini as it merges into Taurus. But more on Gemini and Mars later.

AMATEUR ASTRONOMY:

MARS AND THE MOON:

Three days ago on the evening of the 26th Molly was struck by an intriguing sight that she had forgotten was coming. I'm speaking of the conjunction of Mars with the waning gibbous Moon in the constellation Gemini. Molly tends to shut down her stargazing in the winter months, even though these are perhaps the best of times because Molly hates cold beyond all other things. Thus it was that I was surprised by the sight that I saw. On that evening mars came within 1.5 degree of the Moon, just to the southeast (yes, the photo presented above is from the last conjunction in the spring of this year, so don't berate me too much).

Last Monday's view of Mars was perhaps one of the most striking, but for those with a specific interest in the planet itself it is hardly the best that will occur this year. About every 26 months Mars makes its closest approach to Earth, and this is the time when amateur astronomers have the best view of the red planet. Mars is actually the only planet on which one can see surface detail in the usual backyard scope, though this detail may be obscured this year due to recent dust storms on the planet. This year Mars will rise higher in the sky than it will for any time until 2022. The point of closest approach will be on December 19th. The apparent size of Mars on that date will be about 15.9 arc seconds, far lower than the close approach of 2003 when it had an apparent diameter of 25.1 arc seconds. The best times of viewing will be in the middle of the night. If the dust in the atmosphere has cleared you may be able to see the gradual turning of Mars from night to night because Mars' rotation period is 24 hours and 37 minutes. Thus each night you will see about 1/40th more of the Martian surface towards the East side. As Mars reaches its maximum size in December the northern hemisphere spring will have begun (Martian Equinox is on December 9th). The northern polar icecap will be prominently visible.

The closest approach of Mars to the Earth(88 million kms) will not be exceeded until 2016, and thus this is the best time to observe the surface for another 7 years. On the evening of December 23rd there will be an occultation of Mars by the Moon visible on the west coast and points west of Lloydminster on the Alberta/Saskatchewan border. Further east, such as here in Winnipeg, there will be merely another close approach such as what Molly saw three nights ago.

A FIVE PLANET PARADE:

Through this early part of June the five visible planets will be observable.

VENUS:

Even though Venus reaches its greatest elongation (distance from the sun) this Saturday the planet is already rising less and less in the evening sky each night. The planet is presently located at the crossover from Gemini to Cancer and shines with a bright magnitude 0f -4.4. Venus is the second brightest object in the night sky after the Moon. The planet is presently at a waning half phase and as it enters its waning crescent phase in early July the apparent size of the disc will double from is apparent size as of May 1st. As the crescent of Venus gets thinner and thinner by late July, early August, it will have grown from an apparent size of 16 arc seconds on May 1st to 50 arc seconds.

The end of this month will see a brilliant conjunction on the evening of June 30th when Venus and Saturn pass within 2/3rds of a degree of each other. This will be the closest planetary conjunction of the year and will be best viewed due west between 10pm and 11pm that evening. The two planets will be close enough to be both visible in the eyepiece of a moderate power telescope.

MERCURY:

Though it is presently sinking towards the horizon Mercury is still visible in the western twilight until mid-June. it passed its greatest elongation on June 1st when it shone with a magnitude of +0.4. It now is about +1.2 in magnitude. From 10pm to 11pm for the next few days Mercury can be seen very low in the northwestern sky, to the right and below Venus.

SATURN

As said above Saturn will pass in conjunction with Venus on the evening of June 30th. Saturn is in the constellations Leo , to the east of the position of Venus. Saturn is presently setting before midnight, and it will set earlier and earlier as the month goes on. even though the rings present a good view because of a 17 degree tilt the features of the planet will be less and less visible as the month goes on because the closeness of the horizon will blur the detail. Presently Saturn shines at magnitude +0.5.

JUPITER:

The planet Jupiter is now much brighter than Saturn at magnitude -2.6. This planet reached opposition on June 5th when it began to rise just as the sun set. You will find it in the southeastern to southern sky throughout the nights in the constellation Ophiuchus. This constellation lays on and just above the ecliptic between the constellations of Libra to the west and Sagittarius to the east. Jupiter is usually the second brightest planet after Venus. Its distance from Earth is compensated by the fact that its surface area is 130 times that of Venus. Jupiter will never rise too high in the sky this month(20 degrees elevation at max, and that makes telescopic viewing difficult. Early next Saturday morning here in western North America two of Jupiter's Galilean moons will cast their shadows on the planet's face at the same time. Depending on location this will occur anywhere from 2:17 to 3:03 am this Saturday. This will be a good time for telescopic observation of this planet.

MARS:

This month the planet Mars can be observed at +0.8 magnitude in the constellation Pisces. This means that it lays low in the east in the hours just before sunrise. Mars is presently just to the east of the waning crescent Moon in the hours before dawn, but by June 11th it will have passed to the west, rising earlier and higher throughout the summer.

MARS RISING:

Presently the planet Mars rises in the east southeast about 2 hours before dawn in Aquarius. Its present magnitude of 1 makes it a dim object for viewing in the dawn twilight. In the coming weeks, however, Mars will be rising earlier and progressing into a darker part of the sky, making for better viewing. Throughout the year Mars will be rising progressively earlier until it reaches "opposition" next December. This is also the time when the orbit of the Earth overtakes the slower orbit of Mars and the planets are closest together. At that time Mars will have a magnitude of -1.6, brighter than Sirius. The planet will rise at sunset then and set at sunrise, being highest in the sky around midnight. The closest approach of Mars and the Earth will occur on Dec. 18th when the planets will be about 88 million kilometers apart. The "opposition" when Mars is directly opposite the Sun, rising and setting will actually occur on Christmas Eve. At that time the planet will be best for telescopic viewing.

Just a little heads up here. On August 27th Mars and Earth made a closer approach than they have in 60,000 years, and an email titled 'Mars Spectacular' made its rounds with claims such as Mars being brighter than the full Moon. Seems that every spring and summer the email reappears with its liberal use of exclamation marks. Ignore it. Mars will be better positioned for viewing in the months to come, but the email is a hoax.

Interesting Conjunction Upcoming:
I've already mentioned the upcoming Leonid Meteor Shower due for Dec. 13th and 14th. Another interesting astronomical events will be happening at about the same time, Dec. 7th to 14th actually. This is a triple conjunction of the planets Mercury, Mars and Jupiter in the constellation of Scorpio. The magnitudes of the three planets will be Jupiter: -1.7, Mercury: -0.6 and Mars: +1.5. As you can gather from this Mars will be quite faint, and you will need a good pair of binoculars to spot it. This is compounded by the fact that the best time for viewing will be at about 6:30 AM, and the trio will be quite low in the southeast.
There will be 40 triple conjunctions in the period 1980 to 2050 ie about one every 21 months. Some of these, however, are impossible to observe. The unique aspect of the upcoming one this Dec. is that it will be the "tightest" of any of the events ie the planets will be the closest to each other as compared to other conjunctions. The relative positions of the planets will change over the course of the week of the event.

Sign Up for Space:
The NASA has an interesting offer at their website (http://dawn.jpl.nasa.gov ) for their latest Dawn mission to the asteroids Vesta and Ceres. Seems you can sign your name on for the data base of the spacecraft. Trouble is that the deadline is today, Saturday, Nov. 4th. If you read this before midnight comes hurry on over and send your name to the stars.
If you think this might be a great Christmas novelty gift and you can't make the deadline there's another mission coming up that closes as late as Feb 1st, 2007. You can enter the name of your lucky gift recipient, or yourself, for the Phoenix mission to Mars, due to launch next August. The spacecraft will hold the lucky names in addition to a silica glass DVD holding many of Martian related works from the 19th and 20th century. The title will be 'Visions of Mars'. If you want to fly with the stars or send anyone else to the stars hustle on over to http://planetary.org/phoenixdvd to sign up for this bit of virtual tourism. It's travel with a bang and no passport required.