Protoplanets are small celestial objects that are the size of a moon or a bit bigger. They are small planets, like an even smaller version of a dwarf planet. Astronomers believe that these objects form during the creation of a solar system.
The most popular theory of how a solar system is formed says that a giant cloud of molecular dust collapsed, forming one or more stars. Then a cloud of gas forms around the new star. As a result of gravity and other forces, the dust and other particles in this cloud collide and stick together forming larger masses. While some of these objects break apart on impact, a number of them continue to grow. Once they reach a certain size – around a kilometer – these objects are large enough to attract particles and other small objects with their gravity. They continue to get larger until they form protoplanets. Some protoplanets continue colliding and growing until they form planets while others stay that size.
As the protoplanets grew to become planets, parts of them melted due to radioactivity, gravitational influences, and collisions. Where the objects had melted, the composition of the planets changed. Heavier elements sank, forming the cores of the planets, and lighter objects rose to the surface. This process is called planetary differentiation and explains why planets have heavy cores. Astronomers have discovered that even some asteroids have differentiated, so their cores are heavier than their surfaces.
Protoplanets used to be highly radioactive due to how they were formed. However, over thousands of years, the radioactivity of these objects has greatly decreased because of radioactive decay. Astronomers are still discovering new protoplanets, and most likely, they will discover many more. With better technology, astronomers are now able to find protoplanets in other star systems. Last year, scientists discovered a protoplanet HL Tau b that will probably turn into an actual planet one day. Astronomers say that will not happen for about a million years though because the protoplanet’s star is also very young. In its final form, HL Tau b will look like Jupiter – a gas giant around the same size as that massive planet. It is hard to believe that thousands of years ago our planets were objects about the size of a moon, which were slowly evolving and growing. Astronomers continue to study protoplanets, the same way they study planetesimals, to find out more about how the Solar System was formed.
Dark, cold stars from the young Universe could still be here today (University of Utah)
[/caption]The Big Freeze, which is also known as the Heat Death, is one of the possible scenarios predicted by scientists in which the Universe may end. It is a direct consequence of an ever expanding universe. The most telling evidences, such as those that indicate an increasing rate of expansion in regions farthest from us, support this theory. As such, it is the most widely accepted model pertaining to our universe’s ultimate fate.
The term Heat Death comes from the idea that, in an isolated system (the Universe being a very big example), the entropy will continuously increase until it reaches a maximum value. The moment that happens, heat in the system will be evenly distributed, allowing no room for usable energy (or heat) to exist – hence the term ‘heat death’. That means, mechanical motion within the system will no longer be possible.
This kind of ending is a stark contrast to what other scientists believe will be the Universe’s alternative ultimate fate, known as the Big Crunch. The Big Crunch, if it does happen, will be characterized by a collapse of unimaginably gargantuan proportions and will eventually culminate into an immensely massive black hole. The Big Freeze, on the other hand, will happen with less fanfare since everything will wind down to a cold silent halt.
To determine which ending is most possible, scientists need to gather data regarding the density, composition, and even the shape of the Universe.
For example, if the density is found to be lower than what is known as the critical density, then a continuous expansion will ensue. If the density is equal to the critical density, then the Universe will expand forever but at a decreasing rate. Finally, if the density is found to be greater than the critical density, the Universe will eventually stop expanding and then collapse.
It is therefore clear that, for a Big Freeze to occur, the density must be less than the critical density.
Accurate measurements made by the WMAP (Wilkinson Microwave Anisotropy Probe), which picks up cosmic microwave background radiation (CMBR), indicate a density that is much less than the critical density. This is very consistent with observations at the outer regions of the Universe; that being, increasing outward velocities of galaxies as they are further from us.
Through these observations as well as the density measurements, more scientists are inclined to believe that the most possible ending is that of a Big Freeze.
Articles on the big freeze are so hot. It’s a good thing we’ve got a nice collection of them here in Universe Today. Here are two of them:
The Big Crunch is one of the scenarios predicted by scientists in which the Universe may end. Just like many others, it is based on Einstein’s Theory of General Relativity. That is, if the Big Bang describes how the Universe most possibly began, the Big Crunch describes how it will end as a consequence of that beginning.
It tells us that the Universe’s expansion, which is due to the Big Bang, will not continue forever. Instead, at a certain point in time, it will stop expanding and collapse into itself, pulling everything with it until it eventually turns into the biggest black hole ever. Well, we all know how everything is squeezed when in that hole. Hence the name Big Crunch.
For scientists to predict with certainty the possibility of a Big Crunch, they will have to determine certain properties of the Universe. One of them is its density. It is believed that if the density is larger than a certain value, known as the critical density, an eventual collapse is highly possible.
You see, initially, scientists believed that there were only two factors that greatly influenced this expansion: the gravitational force of attraction between all the galaxies (which is proportional to the density) and their outward momentum due to the Big Bang.
Now, just like any body that goes against gravity, e.g. when you throw something up, that body will eventually give in and come back down for as long as there is no other force pushing it up.
Thus, that the gravitational forces will win in the end, once seemed like a logical prediction. But that was until scientists discovered that the Universe was actually increasing its rate of expansion at regions farthest from us.
To explain this phenomena, scientists had to assume the presence of an unknown entity, which they dubbed ‘dark energy’. It is widely believed that this entity is pushing all galaxies farther apart. With dark energy, and what little is known about it, in the picture, there seems to be little room for the possibility of a Big Crunch.
Right now, measurements made by NASA’s Chandra X-ray observatory indicate that the strength of dark energy in the University is constant. Just for added information, an increasing dark energy strength would have supported the possibility of a Big Rip, another universe ending that predicted everything (including atoms) to be ripped apart.
Even with an unchanging dark energy strength, an ever expanding universe is still the most likely scenario. So unless data that contradicts these properties are collected, the Big Crunch will have to remain as a less favored theory.
Articles on the big crunch are so hot. It’s a good thing we’ve got a nice collection of them here in Universe Today. Here are two of them:
Did you get a chance to check out the IYA “Live” Telescope today? After a prolonged period of clouds and bad weather in Central Victoria, we at least had a partially clear night. Our two objects for the evening were Messier 11 and stunning globular cluster 47 Tucanae. If you didn’t get a chance to see them, why not step inside? We’re making popcorn and playing a re-run…
Since we’ve done both these objects before under better sky conditions, why not show you the better video? Without further ado, here’s some information from Wikipedia:
The Wild Duck Cluster (also known as Messier 11, or NGC 6705) is an open cluster in the constellation Scutum. It was discovered by Gottfried Kirch in 1681. Charles Messier included it in his catalogue in 1764.
The Wild Duck Cluster is one of the richest and most compact of the known open clusters, containing about 2900 stars. Its age has been estimated to about 220 million years. Its name derives from the brighter stars forming a triangle which could represent a flying flock of ducks.
47 Tucanae (NGC 104) or just 47 Tuc is a globular cluster located in the constellation Tucana. It is about 16,700 light years away from Earth, and 120 light years across. It can be seen with the naked eye, and it is bright enough to earn a Flamsteed designation with a visual magnitude of 4.0. It is one of only a small number of features in the southern sky with such a designation.
47 Tucanae was discovered by Nicolas Louis de Lacaille in 1751, its southern location having hidden it from European observers until then. (And even with hazy, moonlit skies, this bad boy was bright in the eyepiece! WOW! I can only imagine what it would look like to see it in person…)
It has 22 known millisecond pulsars, and at least 21 blue stragglers near the core. 47 Tucanae is included in Sir Patrick Moore’s Caldwell catalogue as C106. NGC 104 competes with NGC 5139 for the title: Most splendid Globular Cluster in the sky. NGC 104 has two features in its favour. It is rounder and has a more compact core. However due to location more observers go for NGC 5139.
Until next time, keep on checking the IYA Live Telescope link to your right when you have the chance! Like many areas of the world undergoing seasonal change… It can’t stay cloudy forever. Or can it?
According to AAVSO Special Notice #164 just sent, there is a possible nova candidate in Sagittarius. It was discovered by Koichi Nishiyama, Kurume, Fukuoka-ken, Japan, and Fujio Kabashima, Miyaki-cho, Saga-ken, Japan, at unfiltered magnitude 7.7 on two 60-second frames taken Aug. 6.494 and 6.495 UT. They confirmed the discovery on five frames taken around Aug. 6.494.
Brian Marsden announces in CBET No. 1899 the independent discovery of a possible nova (Nova Sagittarii 2009 No. 3) by Koichi Nishiyama, Kurume, Fukuoka-ken, Japan, and Fujio Kabashima, Miyaki-cho, Saga-ken, Japan, at unfiltered magnitude 7.7 on two 60-second frames taken Aug. 6.494 and 6.495 UT. They confirmed the discovery on five frames taken around Aug. 6.494. No motion was seen during 80 minutes and nothing was visible at this location down to 12.7 on survey frames taken July 22.531 and 29.584 UT. Nothing was seen on the DSS (POSS2/UKSTU red), or in ASAS, AAVSO VSX, SIMBAD, 2MASS and USNO-B1.0 catalogues, although the USNO-B1.0 shows a faint star (I = 12.45) nearby (at end figures 07.509s, 33.13″). Coordinates (from Nishiyama and Kabashima) are: RA = 18h 07m 07.67s, Dec = -33d 46m 33.9s (2000.0)
Finder Chart 3 Degree FOV
According to Elizabeth Waagen of AAVSO, Grzegorz Pojmanski, Dorota Szczygiel, and Bogumil Pilecki, Warsaw University Astronomical Observatory, observed by ASAS3 at V = 7.78 on Aug. 6.182 UT at the approximate position RA = 18h 07m 08s, Dec = -33d 46.6m. Nothing was visible on Aug. 4.152 UT. Leonid Elenin, Moscow, also confirmed (via vsnet-alert 11371) the presence of the object using a remote astrograph in Pingelly, Australia, providing position end figures 07.67s, 34.9s, +/-0.14″. This object has been assigned the name VSX J180707.6-334633 with the AUID 000-BJP-536. Please report observations to the AAVSO International Database using the name Nova Sgr 2009 No. 3 or VSX J180707.6-334633. The ASAS light curve and images can be accessed here. A sequence has not yet been established for this object, but additional finder charts may be plotted by entering the coordinates into VSP.
You’ve all heard me talk about watching the Moon occult a bright star. That’s when we get a great example of stellar parallax from our Earthly viewpoint! But did you know that there are several other heavenly bodies that can cause an occultation that’s easy to view through an amateur telescope if you just know when and where to look? Then let’s take this opportunity to check it out…
On the night of August 3/4, 2009 Leonard Ellul-Mercer of Malta caught this while watching Jupiter!
Jupiter Occults 45 Capricorni Animation by Leonard Ellul-Mercer - Click To Animate
What you’re seeing is a time lapse animation of the mighty Jove occulting HIP 107302, a 6th magnitude star you might know better as 45 Capricorni. How many of us may have glanced at something like that while making a cursory observation of the planet and taken it for a galiean moon? OK… It’s sixth magnitude. Not alot of you, but maybe you might not have watched long enough to know it would occult. (Besides, there’s a whole lot of cool things in that image. Watch the GRS float by, followed by the mushroom impact cloud and the whirl of the moons!)
So how do you go about getting predictions? There’s a wonderful set of worldwide resources that you can find through the International Occultation Timing Association (IOTA). This page will take you to their main frame where you can branch into several areas – including how to time occultations and submit your information. To find information on occultations by planets and asteroids for other areas of the world, be sure to visit the IOTA European section, too!
While you might watch an occultation just for fun, if you do decide to contribute your timing information you’re doing real science. By studying exactly the point in time when a star disappears and reappears, astronomers are able to take more accurate measurements of a planet or asteroid’s size and shape – and better calculate their distances at any given time. It’s a way to engage in new types of complimentary research that doesn’t require multi-million dollar equipment and gives back useful pertinent scientific data. After all, you might possibly discover a new moon of Jupiter – or one too small to be seen by your telescope – in just this way! Even a momentary dimming of a star might mean there’s something more there than meets the eye.
Enjoy your voyage of discovery! There are four major lunar events coming up during the month of August, including another Jupiter/star event for Europe. Get out there and have fun!
Radar imaging at NASA's Goldstone Solar System Radar on June 12 and 14, 2009, revealed that near-Earth asteroid 1994 CC is a triple system. Image Credit: NASA/JPL/GSSR
[/caption]
Radar images have shown that a near-Earth object is actually a triple system; an asteroid with two small moons. NASA’s Goldstone Solar System Radar on June 12 and 14, 2009, revealed the new informaton about Asteroid 1994 CC. It came within 2.52 million kilometers (1.56 million miles) on June 10. Prior to the flyby, very little was known about this celestial body. 1994 CC is only the second triple system known in the near-Earth population. A team led by Marina Brozovic and Lance Benner, both scientists at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., made the discovery.
Asteroid 1994 CC encountered Earth within 2.52 million kilometers (1.56 million miles) on June 10. Prior to the flyby, very little was known about this celestial body. Image Credit: NASA/JPL/GSSR
1994 CC consists of a central object about 700 meters (2,300 feet) in diameter that has two smaller moons revolving around it. Preliminary analysis suggests that the two small satellites are at least 50 meters (164 feet) in diameter. Radar observations at Arecibo Observatory in Puerto Rico, led by the center’s director Mike Nolan, also detected all three objects, and the combined observations from Goldstone and Arecibo will be utilized by JPL scientists and their colleagues to study 1994 CC’s orbital and physical properties.
The next comparable Earth flyby for asteroid 1994 CC will occur in the year 2074 when the space rock trio flies past Earth at a distance of two-and-a-half million kilometers (1.6 million miles).
Of the hundreds of near-Earth asteroids observed by radar, only about 1 percent are triple systems.
Ed von Renouard working at Honeysuckle Creek Tracking Station in Australia was the first person to see images from the Apollo 11 moonwalk. Image courtesty of Bruce Ekert.
Six hundred million people, or one fifth of humanity at the time, watched Neil Armstrong’s first steps on the Moon in 1969. But seeing live transmissions from that historic event wouldn’t have been possible – and the Apollo missions wouldn’t have possible either – without reliable communications and accurate tracking capabilities.
To support the Apollo Program, NASA built the Manned Space Flight Network (MSFN) with three 85 foot (26 meter) antennas equally spaced around the world at Goldstone, California, Honeysuckle Creek, Australia and Fresnedillas (near Madrid), Spain.
Because of the movie “The Dish” however, most people think the Parkes Radio Antenna was the only dish used in Australia. But the Honeysuckle Creek dish was the real star of the Apollo missions. Most notably, it supplied voice and telemetry contact with the lunar and command modules but it also provided the first televised pictures of the Apollo 11 moonwalk.
“It was a job well done by many people all over the world,” said Bruce Ekert, a technician with the Honeysuckle Creek Tracking Station. “When I reflect that we were part of history, it is still amazing that it came together and worked so smoothly.”
The Honeysuckle Creek Tracking Station (HSK) was a radio-quiet location in the Australian Alps surrounded by granite peaks 32km southwest of Canberra, Australia’s capital.
Ekert helped install a microwave relay link from HSK to the Red Hill Radio Terminal in Canberra. “This link was the “missing link” as at that time, there was only a telephone line from HSK to Canberra, and this was unsuitable for TV pictures,” Ekert told Universe Today.
Apollo antenna coverage. Credit: NASA
Ekert was working for the government telecommunications department and in April 1969 he was told his next job would be to install a microwave link so that when Australia’s side of the world was pointed toward the Moon, all the communications to the Moon and back could be relayed to NASA and mission control in Houston.
Honeysuckle Creek Tracking Station during Winter (July) 1969. Photo courtesy Bruce Ekert
It may have been summer in the US, but in Australia it was winter. 1969 was cold and snowy, especially in snow country at 1200m (3600ft) up in the mountains, making the work difficult.
“It was cold and we had a lot of snow that year,” Ekert said, “Aligning microwave dishes on towers in cold weather, the bolts tend to lock up, and it’s difficult to move them around to get the best signal. Moving them with cold hands and cold steel is not the easiest things to do. But we installed microwave dishes on towers and equipment in the buildings. We also had to install a temporary tower with two dishes on it to redirect the signal through the mountains to get it out to the rest of the world.”
“We were running by the seat of our pants at one stage,” Ekert continued. “It was all thrown together and we knew it would work, but still, since we threw it together we hoped it would work according to plan.”
Ekert and his co-workers had to make sure the temporary links stayed working for the duration of the Apollo 11 mission.
“We maintained the equipment in a hands-off position,” he said. “As we say now, if it ain’t broke don’t fix it. We worked for the complete duration of the mission, but we weren’t allowed to touch anything if it was working – just let it run. If it had failed, then we would have had to fix it, but since everything just coasted along and there weren’t any problems, we just watched and waited like everyone else.”
But those at HSK had one little advantage. “The staff at Honeysuckle Creek actually were the first people in the world to see the pictures coming from the Moon, by a few milliseconds,” Ekert said. “So that is our claim to fame.”
Ed von Renouard, working at HSK was the first man in the world to see the pictures from the Moon as they came from the receiver in the dish. (See top image of Ed back in 1969, and below is Ed with Bruce Ekert)
Louise from the HSK reunion organizing committee, Bruce Ekert, and Ed von Renouard at the Apollo 11 celebrations in Australia. Photo Courtesy Bruce Ekert.
But then after 8 minutes, NASA decided the larger 64meter Parkes Radio Telescope, 300 kilometers away, was getting a clearer signal and switched over for the remaining coverage of the spacewalk for the next two-and-a-half-hours.
Yes, there was a wind storm at Parkes, which threatened to blow the dish off course, as portrayed in “The Dish,” but Ekert said the movie was a typical Hollywood type creation.
“There were no crises where they were going to lose communications,” he said. “There was a big storm, where they had winds up to 60 mph (100 kph) at Parkes not long after the landing happened. They did fear the dish might be blown off course, but they always had the standby of Honeysuckle Creek, which was still receiving pictures, and at that point the moon had risen higher in the sky and pictures were actually better. So if the Parkes dish had actually been blown off course, they would have immediately switched back to Honeysuckle Creek.”
The original Honeysuckle dish now at Tidbinbilla. Courtesy Bruce Ekert.
Parkes was part of MSFN’s “wing” stations to provide back-up and additional coverage. This meant that each of the three locations around the world would have two stations capable of communicating with Apollo spacecraft at lunar distances. In addition to just redundancy, there was another reason for having two Apollo-capable stations at each location. For project Apollo, communications used the higher frequency S-Band (around 2.2GHz), and the beam width of the 85 foot antennas at those frequencies was only 0.43 degree. Ideally, one antenna would track the Command Service Module in Lunar orbit and the other would track the Lunar Module to the surface.
Parkes was also called in to assist with the Apollo 13 emergency.
In addition, a number of other stations supported Apollo, including a facility at Tidbinbilla, 20 km away from HSK, which also had dedicated Apollo equipment and people to operate as an additional receive/transmit facility.
More permanent microwave relays were installed, and HSK was part of all the Apollo missions, and in 1974 at the conclusion of the Skylab program, HSK Creek joined the Deep Space Network as Deep Space Station 44, working deep space missions like Viking, Voyager, Pioneer and more. It was closed in December 1981, with its 26 meter antenna relocated to the Canberra Deep Space Communications Complex at Tidbinbilla, and renamed Deep Space Station 46, where it is still in use today.
The original HSK site has been leveled, and only the concrete foundations remain, but in 2001 an outdoor display was added. During Apollo 11 celebrations in July of this year, Ekert joined about 200 other people who worked at HSK, Parkes and Tidbinbilla to commemorate their achievements with Apollo.
Bruce Ekert on July 21, 2009 at the Honeysuckle Creek site, taken from the position of the communications tower. Below is the concrete pad which marks the position of the building. At the very back of the photo is the place where the HSK Dish was situated. Courtesy Bruce Ekert
“We traveled to the site of the HSK tracking station, for a ceremony unveiling a new plaque to show visitors and tourists where history was made on 21st July, 1969,” said Ekert. “We then moved over to another part of the site and a time capsule was filled with memorabilia from 1969 until now. My wife, who is Russian, put in a 50 Ruble note, with the words that there is not a “Cold War” anymore. The time capsule was buried, with instructions for the park rangers that it is to be dug up in 60 years time to mark the 100th anniversary of man’s first footsteps on the moon.”
Neil Armstrong also sent a note of congratulations for the ceremony, touching on the misconceptions the rest of the world might have because of things portrayed in the movie “The Dish.”
“Some of you, I expect, may have had mixed emotions about the film, THE DISH. I understand, because as technical people, we like things to be correct and accurate. And the film did not always accurately capture the roles of those of you at Honeysuckle Creek, those of you at Parkes, and those of you at Tidbinbilla. But for most of the viewers of the film around the world, those were not the details that they would remember anyway. What they will remember is that down in Australia there were some very dedicated people, with some very big antennae and complex electronic equipment that did remarkable things that were instrumental in the success of man’s first flights to the moon. They will have a sense that you were having a great time doing what you were doing. And what they remember will, in fact, be the truth.”
—from Neil Armstrong’s message to the Canberra Deep Space Communications Complex
The celebrations continued in Australia in Canberra and at exactly 12.51pm local time, they showed a replay of the moon walk, with Neil Armstrong jumping down off the ladder of the lunar module to the surface of the Moon at exactly 12.56pm.
Some of the Honeysuckle team underneath the old antenna, DSS-46, at Tidbinbilla on Monday 20th July 2009. Credit: Honeysucklecreek.net
“The audio came over the auditorium sound system, and the atmosphere was awesome,” Ekert said. “It was a great celebration, where we patted ourselves on the back and had a salutatory drink to the whole situation.”
And a well deserved drink it was. The rest of the world sends its thanks to those who made watching television from the Moon possible.
Greetings, fellow SkyWatchers! Have you been watching Jupiter and the Moon make a pass at each other in the early morning sky? What an incredible sight. With the slightly later rise of Selene during the weekend hours, we can take advantage of the earlier evening to do some deep sky studies. However, if you’re just in the mood to kick back in a lawn chair and do a little stargazing, you’ll probably spot some early Perseid meteors gracing the night. I’ll give you a full report on the watching the Perseid Meteor shower just a little bit closer to the date so you won’t forget! For now… Why not join me in the back yard? We’ve got a little history, a little mystery and a telescope waiting for you…
Friday, August 7, 2009 – Today marks the 1726 birth of James Bowdoin, astronomer and friend of Benjamin Franklin. Although Bowdoin suffered many years from consumption, which was finally the cause of his death, he was always vigorous in public affairs. He was one of the founders, and first president, of the American academy of arts and sciences, and left it his valuable library. He also aided in founding the Massachusetts humane society, and in 1779 was made a fellow of Harvard College. He was given the degree of LL.D. by the University of Edinburgh, and was a fellow of the royal societies of London and Edinburgh. Several of his papers appear in the memoirs of the society, among which is one whose object is to prove that the sky is a real concave body enclosing our system, and that the Milky Way is an opening in this, through which the light of other systems reaches us.
What do you think he would have thought if he could be with us tonight as we return to our studies with the globular M14, one of the clusters nearer to the galactic center? Located about 16 degrees (less than a handspan) south of Alpha Ophiuchi (RA 17 37 36 Dec +03 14 45), this 9th magnitude, Class VIII cluster can be spotted with larger binoculars, but only fully appreciated with the telescope.
When studied spectroscopically, globular clusters are found to be much lower in heavy element abundance than stars such as own Sun. These earlier generation stars (Population II) began their formation during the birth of our galaxy, making globular clusters the oldest formations we can study. In comparison, the disk stars have evolved many times, going through cycles of starbirth and supernova, which in turn enriched the heavy element concentration in star-forming clouds. Of course, as you may have guessed, M14 breaks the rules. M14 contains an unusually high number of variable stars—in excess of 70—with many of them known to be the W Virginis type. In 1938, a nova appeared in M14, but it was undiscovered until 1964, when Amelia Wehlau of the University of Ontario was surveying the photographic plates taken by Helen Sawyer Hogg. The nova was revealed on eight of these plates taken on consecutive nights and showed itself as a 16th magnitude star—andwas believed to be at one time almost five times brighter than the cluster members. Unlike 80 years earlier with T Scorpii in M80, actual photographic evidence of the event existed. In 1991, the eyes of the Hubble were turned its way, but neither the suspect star nor traces of a nebulous remnant were discovered. Then, 6 years later, a carbon star was discovered in M14. To a small telescope, M14 will offer little to no resolution and will appear almost like an elliptical galaxy, lacking in any central condensation. Larger scopes will show hints of resolution, with a gradual fading toward the cluster’s slightly oblate edges. A true beauty!
Saturday, August 8, 2009 – On this date in 2001, the Genesis Solar Particle Sample Return mission was launched on its way toward the Sun. On September 8, 2004, it returned with its sample of solar wind particles. Unfortunately, a parachute failed to deploy, causing the sample capsule to plunge unchecked into the Utah soil. Although some of the specimens were contaminated, many did survive the mishap. So what is ‘‘star stuff?’’ Mostly highly charged particles generated from a star’s upper atmosphere flowing out in a state of matter known as plasma.
Before moonrise, let’s study one of the grandest of all solar winds as we seek out an area about three finger-widths above the Sagittarius teapot’s spout as we have a look at the magnificent M8 (RA 18 03 37 Dec +24 23 12). Visible to the unaided eye as a hazy spot in the Milky Way, fantastic in binoculars, and an area truly worth study in any size scope, this 5,200-light-year-diameter area of emission, reflection, and dark nebulae has a rich history. Its involved star cluster—NGC 6530—was discovered by Flamsteed around 1680 and the nebula by Le Gentil in 1747. Cataloged by Lacaille as III.14 about 12 years before Messier listed it as number 8, its brightest region was recorded by John Herschel, and dark nebulae were discovered within it by Barnard.
Tremendous areas of starbirth are found in this region, while young, hot stars excite the gas in a region known as the ‘‘Hourglass’’ around the stars Herschel 36 and 9 Sagittarii. Look closely around cluster NGC 6530 for Barnard Dark Nebulae B 89 and B 296 at the nebula’s southern edge. . .and try again on a darker night. No matter how long you choose to swim in the ‘‘Lagoon,’’ you will surely find more and more things to delight both the mind and the eye!
Sunday, August 9, 2009 – On this date in 1976, the Luna 24 mission was launched on a return mission of its own, not to retrieve solar winds’ samples but lunar soil! Remember this mission as we take a look at its landing site in the weeks ahead. Tonight we’ll return to the nebula hunt as we head about a finger-width north and just slightly west of M8 for the ‘‘Trifid’’ (RA 18 02 23 Dec +23 01 48).
M20 was discovered by Messier on June 5, 1764, and much to his credit, he described it as a cluster of stars encased in nebulosity. This is truly a wonderful observation, since the Trifid could not have been easy to spot, given his equipment. Some 20 years later William Herschel (although he usually avoided repeating Messier objects) found M20 of enough interest to assign separate designations to parts of this nebula—IV.41, V.10, V.11, V.12.
The word ‘‘Trifid’’ was used to describe its beauty by John Herschel. Although M20 is a very tough call in binoculars, it is not impossible with good conditions to see the light of an area that left its home nearly a millennium ago. Even smaller scopes will pick up this faint, round, hazy patch of both emission and reflection, but you will need aversion to see the dark nebula that divides it. This was cataloged by Barnard as B 85. Larger telescopes will find the Trifid as one of the very few objects that actually appears much in the eyepiece as it does in photographs—with each lobe containing beautiful details, rifts, and folds best seen at lower powers. Look for its cruciform star cluster and its fueling multiple system while you enjoy this triple treat tonight!
For now, keep an eye on the sky for the coming of the annual Perseid Meteor Shower! You’ll see a great increase in activity beginning now – despite the moonlight. The peak will be mid-week, but I’ll be back with an update on who, when, where, why and how very soon… Until then? Wishing you clear skies!
This week’s awesome images are (in order of appearance): James Bowdoin (historical image), (credit—NOAO/AURA/NSF), Genesis Spacecraft (credit—NASA), M8: the Lagoon Nebula (credit—NOAO/AURA/NSF), Luna 24 launch (press release photo) and M20: the Trifid nebula (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!
[/caption]
Venus is the second planet from the Sun, orbiting at an average distance of 108.2 million km. Venus takes a total of 224.7 days to orbit the Sun.
The Sun and Venus are vastly different sizes, of course. The diameter of Venus is 12,103 km, while the diameter of the Sun is 1.4 million km. In other words, the Sun is 115 times larger than Venus. You could fit about 1.5 million planets the size of Venus inside the Sun.
Venus is a terrestrial planet. It has a metal core surrounded by a mantle of silica rock. This is surrounded by a thin crust of rock. The Sun, on the other hand, is a massive ball of hydrogen and helium gas. Temperatures at its core are hot enough to ignite nuclear fusion – more than 15 million Kelvin.
The Sun has an enormous impact on Venus. The radiation from the Sun is trapped by the thick atmosphere of Venus, raising average temperatures across the planet to around 460 °C. In fact, this makes Venus the hottest planet in the Solar System.
Both the Sun and Venus formed at the same time, 4.6 billion years ago, with the rest of the Solar System. They formed out of the solar nebula, a cloud of gas and dust that collapsed down to become the Sun and planets.
Because Venus orbits closer to the Sun than the Earth, we always see it close to the Sun in the sky. Venus is either trailing the Sun or leading it across the sky. The best times to see Venus are just before sunrise or just after sunset.
