The Night Sky Guy

Moon Meets with Mars’ Rival Tonight

Click image to enlarge

Face the southern horizon tonight after dusk and you can see the waxing gibbous Moon pointing the way to a brilliant orange coloured star known as Antares.  If you have never seen this star before, this is a nice opportunity to track it down thanks to the Moon - Antares is a beauty as it sparkles near the horizon. It’s name means the ‘Rival of Mars’ since it reminded ancient astronomers of the Red planet, which looks very similar in the sky.

Despite Antares being located just over a whopping 600 light years from us it still ranks as the 16th brightest star in the entire sky. Astronomers classify it as a red super giant star - and for good reason. Antares’ shines 10,000 times brighter than our puny Sun and has a diameter that is truly monsterous- 800 times bigger than the Sun. Anteres is the lead star in the constellation Scorpius, which is a landmark for summer skywatchers. Over the course of the next couple of months,  the Scorpion will rise a bit higher above the southern horizon in the evenings, making it an easier target to observe.

Bookmark

Amazing New Moon Pics from NASA Probe

NASA’s Lunar Reconnaissance Orbiter, or LRO, has transmitted its first images since reaching lunar orbit June 23. The spacecraft has two cameras — a low resolution Wide Angle Camera and a high resolution Narrow Angle Camera.

Collectively known as the Lunar Reconnaissance Orbiter Camera, or LROC, they were activated June 30. The cameras are working well and have returned images of a region a few kilometers east of Hell E crater in the lunar highlands south of Mare Nubium.

 

image shows a region 1,400 meters wide.

Bookmark

Unlocking Martian Water Cycle Mystery

According to the first findings from the Phoenix Mars Lander mission, snow and water-ice clouds play a crucial role in the exchange of water between the atmosphere and surface of Mars, which suggests that the Red Planet is even more like Earth than previously thought.

In September 2008 Phoenix films water-ice clouds moving across Martian arctic skies

 The surprise discovery of Martian snow in 2008 by the  Canadian-built weather station on NASA’s Phoenix Mars lander helps explain how the water cycle on Mars behaves, especially the seasonal increase of the Martian polar caps in winter and their consequent shrinking in summer. The Canadian team describes in their scientific paper published this week, how water vapour is lofted upwards during the daytime, forming clouds of ice-crystals low in the atmosphere that resemble cirrus clouds on Earth. Water then precipitates through the atmosphere at night in the form of snow.  ”It’s similar to the phenomenon known as ‘diamond dust’ in the Arctic. If you look up into the Arctic night sky, you see fine ice crystals falling softly towards you,” said Jim Whiteway, of York University, lead scientist for Phoenix’s Meteorological Station. “You can still see the stars but it is like a continuous, light snowfall in the form of ice crystals.”

 Prior to the Phoenix mission, scientists had not anticipated precipitation on Mars, nor had they predicted that clouds would form as low as they did.  ”We knew that the polar ice cap advanced as far south as the Phoenix site in winter, but we didn’t know how the water vapor moved from the atmosphere to ice on the ground,” said Whiteway. “Now we know that it does snow, and that this is part of the hydrological cycle on Mars.”

Phoenix's LIDAR green laser

Within hours of landing, Phoenix’s Meteorological Station began beaming back data on the temperature and pressure at the landing site, and measured dust, clouds and fog in the lower atmosphere. The warmest temperature recorded during the mission was minus 19.6 degrees Celsius, with the coldest at minus 97.7 degrees Celsius. Canada’s lidar instrument on Phoenix (a shoe-boxed sized laser instrument) probed the Martian atmosphere daily throughout the mission for a total of approximately 137 hours of operating time (about 1 hour each Martian day), emitting 49 423 600 laser shots. Perched at the top of the meteorological station’s mast, the wind indicator (known as the “telltale”), measured wind speed and direction and detected the presence of several dust devils at the landing site. Winds at the Phoenix landing site were typically between 3-5 metres/second (11-18 km/h), which increased to an average of about 10 m/s (36 km/h) during the last 50 sols of the mission, when winter weather started to set in. The highest recorded wind speed was 16 m/s (58 km/h).

- Adapted from material provided in Canadian Space Agency press announcement

Bookmark

Baby Solar Systems Discovered

University of Hawaii

Two University of Hawaii astronomers have found a binary star-disk system in which each star is surrounded by the kind of dust disk that is frequently the precursor of a planetary system. A binary star system consists of two stars bound together by gravity that orbit a common center of gravity. Most stars form as binaries, and if both stars are hospitable to planet formation, it increases the likelihood that scientists will discover Earth-like planets.
 
This binary system, 253-1536, stands out as the first known example of two optically visible stars, each surrounded by a disk with enough mass to form a planetary system like our own. It lies 1,300 light-years from Earth, in the famous Orion Nebula, the kind of rich cluster of stars that is a common birth environment for most stars in our Milky Way galaxy, including our Sun.

Orion Nebula

The two stars are 400 times farther from each other than Earth is from the Sun. They would take 4,500 years, or about the length of human recorded history, to complete one orbit around their common center. Both stars are only about a third the mass of our Sun and are much cooler and redder in color. Viewed from a potential future planet, the stellar neighbor would appear as an intense point in the night sky, about one thousand times brighter than the brightest star in our night sky, Sirius. Planets around the other star would be visible only through telescopes, but they would be within reach of spacecraft from a civilization with the same level of technology as ours.
 
The larger disk in 253-1536 is also the most massive found in the Orion Nebula so far. The discovery of this massive disk and the binary disk system improve our understanding of how common planet formation is in our Galaxy and place our Solar System in context.

Adapted from material taken from University of Hawaii news annoucement

Bookmark

Moon and Spica makes Pretty Pair

click to enlarge

Over the next two nights watch the gibbous Moon glide by the bright star Spica in the southwest horizon after dusk. The pair promises to be quite eye-catching. While the Moon makes it easy to find this 16th brightest star in the sky the next couple of evenings, there is another way you can hunt down Spica when it’s by its lonesome.  A good stargazing trick is to start off at the Big Dipper - which is upside down, high overhead in the evenings. Draw an imaginary line through the Dipper’s handle, out its end and down to the next brightest star - named Arcturus. Then continue following that imaginary line to the next brightest star, which is Spica.  So you Arc to Arcturus, and Spike to Spica. It’s as easy as that.

click to enlarge

By tomorrow night the Moon will have moved again towards the southern sky, and will have shifted to the left of Spica. Look carefully and you might notice that the two are much closer together than the night before, making it more interesting sight.

By the end of the week the Moon will slowly continue its daily motion and will pair up with sparkling orange coloured star Antares, the lead star in the constellation Scorpius - another cool cosmic event. More details on that coming later this week, so stay tuned.

Bookmark

Saturn, Moon, Spica Sandwich in the Sky

click to enlarge

Bookmark

Moon Snuggles with Saturn this Weekend

click to enlarge

This evening the Moon has shifted towards the southern sky a bit so that it hangs just below planet Saturn. The pair together will look quite impressive to the unaided eye - even if you live in the city. It’s amazing to think that while the Moon is only about 400,000 km away, the ringed-planet sits over 1.2 billion km from Earth. Despite its vast distance, Saturn shines so bright in the sky because of it’s massive size - 9 times larger than Earth, and its highly reflective cloud-tops. To the naked eye the 6th planet in the solar system shines with a creamy-yellow colour- which is the actual colour of its gaseous atmosphere. 

click to enlarge

 To see Saturn’s famous rings however you will need a small telescope.  It doesn’t have to be a fancy instrument- anything bigger than a pair of binoculars should give you a glimpse. These rings are made of billions of chunks of ice and rock - everything from house-size down to a the size of a particle of dust. They are about 250,000 km wide, which would make the planet with its rings fit snuggly in between the Earth and the Moon. The rings have been getting narrower in the eyepiece over the past year as the tilt of the planet - to our line of sight - has made the rings appear extremely thin. A small telescope will also reveal a handful of the largest of the 60 or so moons Saturn has zipping around it.

Bookmark

Luna and the Lion’s Heart Tonight

click to enlarge

If you have clear skies tonight check out a beautiful crescent Moon pairing up with the  bright star, Regulus in the southwest horizon at around 10 pm. Up until a few hundred years back, this blue-white star was called officially by its Latin name - Cor Leonis - The Lion’s Heart’. It is the brightest star in the constellation Leo and if you lookat the outline of the mythical figure, Regulus definitely does mark the spot where the lion’s heart would be.

Regulus is about 77 light years away and is larger and much younger than our own Sun - 3.5 times bigger and only a few hundred million years old.  What you may not know is that it is in fact a multiple star system consisting of 4 different stars that revolve around each other in pairs. Also recent observations of this bright star has revealed that its spins so fast around its axis, that its shape is distorted resembling an egg. While our Sun rotates on its axis in about 24 hours, Regulus takes only 16 hours !

Bookmark

Brightest Summer Star is Magnetic

Astronomers today announced the first detection of a magnetic field on the star Vega, one of the brightest stars in the sky. Vega is a famous star among amateur and professional astronomers. Located at only 25 light years from Earth in the Lyra constellation, it is the fifth brightest star in the sky. It has been used as a reference star for brightness comparisons. Vega is twice as massive as the Sun and has only one tenth its age. Because it is both bright and nearby, Vega has been often studied but it is still revealing new aspects when it is observed with more powerful instruments. Vega rotates in less than a day, while the Sun’s rotation period is 27 days. The intense centrifugal force induced by this rapid rotation flattens its poles and generates temperature variations of more than 1000 degrees Celsius between the polar (warmer) and the equatorial regions of its surface. Vega is also surrounded by a disk of dust that suggests the presence of planets.

Find Vega near overhead summer night skies

This time, astronomers analyzed the polarization of light emitted by Vega and detected a weak magnetic field at its surface. This is really not a big surprise because one knows that the charged particle motions inside stars can generate magnetic fields, and this is how solar and terrestrial magnetic fields are produced. However, for more massive stars than the Sun, such as Vega, theoretical models cannot predict the intensity and the structure of the magnetic field, so that astronomers had no clue to the strength of the signal they were looking for. After many unsuccessful attempts in past decades an observing campaign have made this first detection possible.

The strength of Vega magnetic field is about 50 micro-tesla, which is close to that of the mean field on Earth and on the Sun. This detection suggests that magnetic fields exist but have not been detected yet on many stars like Vega. Astronomers believe that this discovery will be a key step in understanding stellar magnetic fields and their influence on stellar evolution. As for Vega, it is now the prototype of a new class of magnetic stars and will definitely continue fascinating astronomers for years.

Bookmark

Watch NASA Moon Probes LIVE

NASA’s two lunar orbiters are closing in on their final destination this morning and you can catch the latest views with streaming video being sent by one of the spacecrafts visible light camera LIVE on the internet along with real-time telemetry of exactly where it is in space.  Click here to watch!

Bookmark