Universe Today

July 24, 2009December 24, 2015 by Nancy Atkinson

Hubble Powers Up to Capture Jupiter Impact Site

This Hubble picture, taken on July 23, by the new Wide Field Camera 3, is the sharpest visible-light picture taken of the atmospheric debris from a comet or asteroid that collided with Jupiter on July 19. Credit: NASA, ESA, and H. Hammel (Space Science Institute, Boulder, Colo.), and the Jupiter Impact Team

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The Hubble Space Telescope was undergoing a thorough checkout of all its systems following the recent servicing mission, but scientists decided to drop everything and interrupt the observatory’s checkout and calibration to take an image of what every other telescope has by trying to view: the impact site on Jupiter. But Hubble does it better than anyone. This image, taken just yesterday (July 23) shows the black spot on the giant planet — created a small comet or asteroid — is expanding.

“Because we believe this magnitude of impact is rare, we are very fortunate to see it with Hubble,” said Amy Simon-Miller of NASA’s Goddard Space Flight Center in Greenbelt, Md. “Details seen in the Hubble view shows a lumpiness to the debris plume caused by turbulence in Jupiter’s atmosphere.”

The new Hubble images also confirm that the May servicing visit by space shuttle astronauts was a big success.

The Jupiter impact has been a sensation ever since Australian amateur astronomer Anthony Wesley imaged a black spot on the planet on July 19. , The only other time such a feature has been seen on Jupiter was 15 years ago after the collision of fragments from comet Shoemaker-Levy 9.

For the past several days, Earth-based telescopes have been trained on Jupiter. To capture the unfolding drama 360 million miles away, Matt Mountain, director of the Space Telescope Science Institute in Baltimore, gave observation time to a team of astronomers led by Heidi Hammel of the Space Science Institute in Boulder, Colo.

“Hubble’s truly exquisite imaging capability has revealed an astonishing wealth of detail in the impact site,” Hammel said. “By combining these images with our ground-based data at other wavelengths, our Hubble data will allow a comprehensive understanding of exactly what is happening to the impact debris.”

Simon-Miller estimated the diameter of the impacting object was the size of several football fields. The force of the explosion on Jupiter was thousands of times more powerful than the suspected comet or asteroid that exploded over the Siberian Tunguska River Valley in June 1908.

The image was taken with the Wide Field Camera 3. The new camera, installed by the astronauts aboard space shuttle Atlantis in May, is not yet fully calibrated. While it is possible to obtain celestial images, the camera’s full power has yet to be seen.

“This is just one example of what Hubble’s new, state-of-the-art camera can do, thanks to the STS-125 astronauts and the entire Hubble team,” said Ed Weiler, associate administrator of NASA’s Science Mission Directorate in Washington. “However, the best is yet to come.”

Source: NASA

July 24, 2009March 24, 2012 by Nancy Atkinson

Company Flies Biofuel Rocket (Video)

Flometrics, Inc. successfully flew a liquid fueled rocket with a 100% renewable fuel, a version of JP-8 (Jet Propellant 8) and liquid oxygen. The 180 lb (81 kg) rocket was 20 feet (6 meters) tall, 1 foot (.3 meters) diameter and it was powered by a RocketDyne LR-101 rocket engine that was originally used as a steering engine on the early Atlas and Delta rockets. The rocket performance during the 15 second long burn was better than the performance of a similar rocket using RP-1 refined kerosene rocket fuel. It reached an altitude of approximately 20,000 ft (6096 m) and may have exceeded Mach 1. The biofuel ran cleaner than the standard rocket fuel that has been used before. Since the biofuel was originally designed for jets, it may be possible to tune it for better performance in rocket engines. The fuel was developed by the Energy and Environment Research Center (EERC) at the University of North Dakota.

Source: Flometrics

July 24, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast: July 24-26, 2009

Greetings, fellow SkyWatchers! Has everyone enjoyed the Apollo revival? I certainly have – and now the Moon is gently returning to evening sky and offering us great opportunities over the coming evenings to do a little bit of study with binoculars and telescopes. Look for its slender crescent just after sunset! This weekend we’re going to try an open cluster you may never have seen that works well for small optics and a Herschel object with a real twist. Need more? Then we’ll check out a beautifully colored double star, too… But not the one you expect! Grab your telescopes and binoculars and I’ll see you in the back yard…

Friday, July 24, 2009 – Today let’s start with the 1853 birth on this date of Henri-Alexandre Deslandres. Do you recognize his name from our lunar studies? He invented the spectroheliograph to photograph the Sun in monochromatic light! Deslandres also observed the spectra of planets and stars and measured their radial velocities. Did you see the very young crescent of the Moon during twilight? The Moon played an important role in history on this date. The Apollo 11 astronauts splashed down from their return from the Moon on this date in 1969! Only 15 years before, in 1954, the sound of a human voice had been reflected off the Moon’s surface and returned to Earth. James H. Trexler at the Naval Research Laboratory spoke into a microphone at the laboratory’s Maryland facility, and the sound was relayed back 2.5 seconds later. Although ‘‘Operation Moon Bounce’’ was only a repetition of vowel sounds, Trexler felt the project held promise as a communications and radar intercept device. It might be worth it to point out that many radars are very close to the theoretical possibility of contacting the Moon, and hence the practicality of building a system capable of intercepting these systems by reflections from the Moon is not beyond the realm of possibility.

Tonight we start with a group of young stars beginning their stellar evolution and end with an old solitary elder preparing to move onto an even ‘‘higher realm.’’ Open cluster IC 4665 is easily detected with just about any optical aid about a finger-width north-northeast of Beta Ophiuchi (RA 17 46 18 Dec +05 43 00). Discovered by Philippe Loys de Cheseaux in the mid-1700s, this 1,400 light year distant cluster consists of about 30 mixed-magnitude stars all less than 40 million years of age. Despite its early discovery, IC 4665 did not achieve broad enough recognition for Dreyer to include it in the late nineteenth-century New General Catalog (NGC), and it was later added as a supplement to the NGC in the Index Catalog of 1908. Be sure to use low power to see all of this large group.

Saturday, July 25, 2009 – Today we celebrate a success of the U.S.S.R. space program with the achievement of cosmonaut Svetlana Savitskaya, the first woman to walk in space (in 1982 on this date) and only the second female to go into space, preceding Sally Ride. Today is also the date of the 1973 launch of Soviet Mars 5 probe. Although it didn’t complete its full mission, it did send back 60 photos of the Martian Southern Hemisphere!

Although poor position makes study difficult during the first few lunar days, be sure to look for the ancient impact Vendelinus. Spanning 150 kilometers in diameter and with walls reaching up to 4,400 meters in height, lava flow has long ago eradicated any interior features. Its old walls hold mute testimony to later impact events such as crater Holden on the south shore, larger Lame on the northeast edge, and sharp Lohse northwest. Mark your challenge list!

Tonight’s challenge is Herschel I.44, also known as NGC 6104, a 9.5-magnitude globular cluster around two finger-widths northeast of Theta Ophiuchi and a little more than a degree due east of star 51 (RA 17 38 37 Dec –23 54 31). Discovered by William Herschel in 1784 and often classed as ‘‘uncertain,’’ this halo object has been pegged by today’s powerful as a Class VIII and given a rough distance from the galactic center of 8,800 light-years. Although neither William nor John could resolve this globular and listed it originally as a bright nebula, studies in 1977 revealed a nearby suspected planetary nebula named Peterson 1. Thirteen years later, further study revealed this wasn’t a nebula at all but evidence of a symbiotic star. Symbiotic stars are a true rarity—not a single star at all but a binary system. A red giant dumps mass toward a white dwarf in the form of an accretion disk. When this reaches critical mass, it then causes a thermonuclear explosion, resulting in a planetary nebula. Although no evidence exists that this object is located within metal-rich NGC 6401, just being able to see it in the same field makes this journey both unique and exciting!

Sunday, July 26, 2009 – On this date in 1969 in a vacuum-sealed room, the very first sample return of Moon rocks was studied.

Our own vacuum of space awaits as we view the area around Mare Crisium to have a look at this month’s lunar challenge—Macrobius.

You’ll find it just northwest of the Crisium shore. Spanning 64 kilometers in diameter, this Class I impact crater drops to a depth of nearly 3,600 meters—about the same as many of our Earthly mines. Its central peak rises to 1,100 meters and may be visible as a small speck inside the crater’s interior. Be sure to mark your lunar challenge lists, and look for other features you may have missed before!

Since the moonlight will now begin to interfere with our globular cluster studies, let’s waive these for a while as we take a look at some of the region’s most beautiful stars. Tonight your goal is to locate Omicron Ophiuchi, about a finger-width northeast of Theta (RA 17 18 00 Dec –24 17 02). At a distance of 360 light-years, the Omicron system is easily split by even small telescopes. The primary star is slightly dimmer than magnitude 5 and appears yellow to the eye. The secondary is near 7th magnitude and tends to be more orange in color. This wonderful star is on many doubles’ observing lists, so be sure to note it!

Are you wanting to keep an eye out for those dark markings of the Jupiter impact, too? Well, they’re there! Just remember if you’re new to astronomy that features on Jupiter rotate as the planet turns and we’re turning, too. Seeing the new “spots” requires some calculations and these areas will rotate into meridian view about 2 hours and 6 minutes after the Great Red Spot makes an appearance. Also remember that our own atmospheric seeing conditions play a great role as well! If it just so happens the dark spots will be making their appearance will Jupiter is still very low on the horizon, chances are your luck with seeing them in a small telescope won’t be high. But, don’t let that discourage you from looking! It doesn’t take long for a planet to rise to good observing height and the spots will stay visible for several hours as they rotate in and out on either side of your computed appearance time. (And don’t forget galiean moon shadow transits can also cause dark markings… but these will be very round!)

Until next week? Enjoy your observations and keep reaching for the stars!

This week’s awesome images are (in order of appearance): Henri Deslandres (historical image), IC 4665 (credit—Palomar Observatory, courtesy of Caltech), Vendelinus (credit—Alan Chu), NGC 6401 (credit—Palomar Observatory, courtesy of Caltech), Macrobius on the edge of Crisium (credit—Greg Konkel) Omicron Ophiuchi (credit—Palomar Observatory, courtesy of Caltech) and Jupiter (credit-Sky & Telescope: Sean Walker). We thank you so much!

July 24, 2009December 24, 2015 by Nancy Atkinson

Giant Soap Bubble In Space

The Cygnus Bubble. Credit: T. A. Rector/University of Alaska Anchorage, H. Schweiker/WIYN and NOAO/AURA/NSF

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What looks like a giant soap bubble or even perhaps just a water drop on a camera lens is actually a newly discovered planetary nebula. Dave Jurasevich of the Mount Wilson Observatory in California spotted the “Cygnus Bubble” while recording images of the region in July 2008. A few days later, amateur astronomers Mel Helm and Keith Quattrocchi also found it. Then, in 2009, the Kitt Peak Observatory pointed its 4-meter Mayall telescope at the object, and created the image above. Spectacular!

The bubble has been there awhile, and probably won’t “pop” anytime soon. The object was officially named PN G75.5+1.7 just last week. Astronomers have looked back at older images and found the object, just barely discernible in some images, such as this image below taken by Jurasevich.

Faint "Bubble" Nebula in Cygnus - Imaged on 05 July 2008 by Dave Jurasevich

A closer look at images from the second Palomar Sky Survey revealed it had the same size and brightness 16 years ago. Jurasevich thinks it was overlooked because it is very faint.

“It’s a beautiful example,” says Adam Frank of the University of Rochester, New York. “Spherical ones are very rare.” One explanation is that the image is looking down the throat of a typical cylindrical nebula. However, it is still remarkably symmetrical, Frank says.

For more about the history of observing this object, check out this post on Jurasevich’s Star Imager site.

Source: New Scientist

July 24, 2009December 24, 2015 by Nancy Atkinson

The Grand Canyon From Space

Grand Canyon from space. Click for larger version. Credit: ESA

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The Grand Canyon is an awesome sight on Earth — one of the seven natural wonders of the world – and it looks breathtaking from space, too. This image was taken by the Envisat satellite, showing canyon walls, rock structures, old lava flows, buttes, ravines, stair-step topography in hues of pink, violet and gray.

Also visible in the image are the Colorado Plateau (upper right corner), the Mogollon Plateau (dark area under Colorado Plateau), Lake Meade (Y-shaped water body left of the canyon), Las Vegas, Nevada (bright white and blue area left of Lake Meade) and the southern tip of Utah (upper left).

Although a number of processes combined to create the Grand Canyon, it was formed primarily by the eroding action of the Colorado River that began about six million years ago. Other contributing factors include volcanism, continental drift and the semiarid climate.

As water erosion sculpted this majestic showplace, it revealed layers and layers of exposed rocks that provide us with a profound record of geologic events. As some of Earth’s oldest rock lies at the bottom of the canyon, it is said to be 1800 meters and a billion years deep. It is about 443 km long and 8 to 29 km wide.

This image was acquired by Envisat’s Medium Resolution Imaging Spectrometer (MERIS) instrument on 10 May 2009, working in Full Resolution mode to provide a spatial resolution of 300 meters.

Source: ESA

July 24, 2009December 24, 2015 by Nancy Atkinson

Company Looks to Etch Advertising on the Moon

A new company is looking to sell advertising on the Moon. No, not with giant billboards, but by a new technology called Shadow Shaping that can creates images with robots that carve small ridges in the lunar dust over large areas that capture shadows and shape them to form logos, domains names or memorials.

“Never in the history of advertising has the possibility of penetrating every market on Earth, reaching every person on the planet, and touching them at emotional level only possible with the beauty of the moon on a starlit night, been made available,” says the website for Moon Publicity. “Twelve billion eyeballs looking at your logo in the sky for several days every month for the next several thousand years.”

Bid now for this exclusive ad space, starting at $46,000 (USD).

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Isn’t this going a bit far, proposing to change the face of the Moon? The Moon Publicity people say they are doing this for the benefit of mankind.

“Advancements in space robotics as a result of Shadow Shaping, will aid in the colonization of outer space, helping preserve mankind from the inherent dangers of placing all of our species’ eggs in one basket, planet Earth. Any number of catastrophic events could end human life on Earth: Pandemics, collisions with comets or asteroids, weapons of mass destruction, supercollider accidents, environmental changes, hypernova radiation or the expansion of the Sun.”

“If shadows form a logo during a quarter moon, it will be a small price to pay for saving mankind.”

The website goes on to say that creating images on the Moon provides a commercial incentive for turbo charging space travel technology. “Shadows are only the beginning. These advancements will eventually place robots on other worlds building space stations and planting crops.”

Hmmm.

Source: Space Coalition Blog

July 24, 2009April 26, 2016 by Tammy Plotner

Vixen R130Sf Newtonian Reflector Telescope and PortaMount II – Right In The Comfort Zone…

So what’s the latest telescope I’ve been testing? This time it’s a Vixen R130Sf Newtonian Reflector Telescope and PortaMount II. I can tell you right now that I’ve never laid my hands on a telescope that I was more comfortable with out of the box than this one… But, I guess I really need to start the story from the beginning, don’t I? Then follow me over to the Observatory and I’ll tell you how this charming Vixen stole my heart away.

Quite frankly, folks, as the head of a non-profit organization it’s my job to beg. Sure, I’d love to be sitting in an air conditioned office in a swivel chair telling my secretary to send out a purchase order for equipment – but that ain’t happening. At WRO, we don’t charge anything for our public programs, educational outreach, planetarium programs, or even visiting schools, libraries, or doing guest speaker shots. That’s just the way it is. Astronomy education should be free and we’re gonna’ keep it that way. So, when the time comes each year for us to give our Hidden Hollow Star Party, somebody has to approach a whole lot of astronomy equipment manufacturers and humble themselves to try to get door prizes. Those door prizes then go into a raffle where you buy tickets and that’s how we make our operating money.

You know, the good stuff like electricity, toilet paper, trash bags and coffee…

In these economic times, it’s not easy for any company to donate anything – much less something valuable. That’s why we were completely stunned when Janet D. of Vixen Optics told us they would donate a Vixen R130Sf Newtonian Reflector Telescope and PortaMount II. We would have been thrilled with a plossl eyepiece. Can you imagine how I felt when I got that news? My starz… We might even sell enough raffle tickets on that one to be able to afford to have new Styrofoam cups this year! Needless to say, we were incredibly honored and we knew that we’d have to take it out of the box to display it.

Can we have first light?

Needless to say, the guys were on it the moment the boxes made it to the concrete pad. Tape was cut, packing materials carefully removed and restored, optics gently lifted and ready for assembly. You know what? The Vixen PortaMount II is the easiest mount I’ve ever put together. Not one thing on it fought me. The HAL 130 tripod slicked right into place at the perfect height and I was totally delighted to see captive screws on both the mount and accessory tray that meant nothing was going to get lost in the dark. The tripod itself is very light aluminum, weighing in at right around 12 pounds . But, it’s by no means “cheap”. The legs are high grade material and extend from just about 32″ to just a little over 50″. The tube rings for the scope weren’t cheaply made either. The hinges didn’t “flap” when they were open. The just connected perfectly to the famous Vixen dovetail, the dovetail slid into place and the two knobs that hold it were very easy on arthritic hands.

Now for the optical tube. Again, the scope rings didn’t flap around like broken bird wings when you opened them and they fit comfortably around the OTA. You didn’t feel like you had to torque it down to make it hold the tube and the felt lining made it just right so it was easy to rotate the tube and not even disturb the mount’s position. The scope body is well crafted. It’s lightweight at less than 20 pounds – but it has a very solid feel to it. Trim rings and mirror cells are finished well… not just covered like an afterthought. The four-vane spider is rock solid, but I’ll warn you in advance the primary mirror isn’t center marked. In this case, it’s a small scope. It really doesn’t need to be. The 2″ rack and pinion style focuser is nice and solid and doesn’t slop around. It has good tension and appears to be very well machined for lasting quality.

Now for the finderscope. Ah, yes… Vixen did this one right, too. No hookey jookie red dots or telrads here. Just a very generous 6×30 optical finderscope on a sturdy little bracket with spring tensioners to fine tune it. What’s that you say? Uh, huh. Well, let’s see you use your red dot finder when the batteries run out and you’ve got 75 kids waiting to see something and the nearest department store is 15 miles away. And ya’ wanna’ know what else? The daggone thing was less than a degree off center right out of the box! I had a hard time believing it until I saw it with my own eyes.

Oh, I’m getting more comfortable by the minute here.

Next? Balance. Geez, Louise… I want to meet the guys that designed these things, because I didn’t have to move the optical tube more than an inch from where I first laid it in the rings to hit balance. The Vixen PortaMount II is an absolute engineering work of art. There’s a little cubby built in with tools should you need to adjust the tension for the alt-az, but it just didn’t need it. Just the slightest amount of friction tension was all it took and no matter what position you put the scope in, it just stayed there. Quite frankly, after having used a whole lot of clunky German equatorial mounts over the years, I was amazed. I’ve used alt-az, too… But nothing of this caliber. It’s like an incredibly well balanced dob… with legs! I’ve attached the slow motion controls, which can be put on either side of the axis, but unless you were using ridiculously high magnification, just a slight touch of the hand keeps this scope where you want it to be. Thanks to the high quality of the PortaMount II, it is just that comfortably balanced.

So, now we’re off to the optics test. Well, finally. A little flaw at last or one of you out there is going to accuse me of gushing Vixen because they donated a scope. If you’ve been paying attention, then you know the key word here is Vixen R130Sf Newtonian Reflector Telescope. And what will happen to any reflector telescope that’s made a 3,000 mile trip via UPS? Yeah. It needed collimated. Painful process involving lasers, artificial stars and much pulling of hair and gnashing of teeth? No. Just a tweak with a screwdriver. Just like the finderscope, it only needed the most minor of adjustments to be put right back where it belonged.

In the comfort zone…

But! Back to the optics. The Vixen R130Sf Newtonian Reflector Telescope came with two eyepieces – a 20mm and 6.3mm – and this weird looking extension I wasn’t familiar with. Perhaps the 1.25″ adapter? Well, as soon as I put in an eyepiece to do anything more serious than align the finder, I figured it out. The extension/adapter needs to be screwed over the focuser drawtube to bring the eyepiece out to the proper focal length for perfect focus for these eyepieces. It’s a little unusual, but I didn’t walk out of the cornfield yesterday, you know. The Vixen R130Sf is a 650mm focal length f/5 and I’d rather have an eyepiece extender incorporated into the design than have an added lens down inside to rob more light and collect dust. Once in place? Blam! Razor sharp focus and all we need is dark…

And I’m feeling really comfortable.

The Milky Way came out to sing and dance that night and the R130Sf Newtonian Reflector Telescope on a PortaMount II did Vixen proud. Without being tied to the restrictions of the EQ, I was all over the sky. It was simply nothing to find 10 Messier objects within minutes – and even share the view. I always have great fun when I’m observing with a bunch of guys with GoTo scopes and we race to see who gets there first, eh? By the time they get done aligning everything and punching buttons, I’m already two past you. But then, give me a faint, vague fuzzy and it make take an hour and six star charts. The real kicker for me is just that it is a pure scope. It doesn’t require batteries, electric cords or power packs. Just a little sky knowledge and patience are all it takes.

So how was the view? We’re talking about a telescope with an aperture of slightly over 5″ and the ability to reach at least 12th magnitude. Low power delivered great rich field, but did have just a tiny little band of coma around the outside edge. Perhaps this is something that would bother someone like say, oh, an astrophotographer, but at first I was too busy being delighted on its nebula performance to even notice. Those little touches like being able to see the Trifid nebula mean alot to me, you know. Higher magnification delivered smack you in the eye resolution on objects like globular clusters and planetary nebula… And I just didn’t have the heart to try other eyepieces in it to see if it cleared up the slight coma issue. Why?

Because I was so darned comfortable.

I walked all over the night sky with that Vixen telescope, and it’s gonna’ break my heart to see it go. I’ve handled a lot of expensive, exquisite optics over the years – just like I’ve handled a lot of gotta’ be careful with ’em because they’re cheap scopes… But I’ve never ran across one that felt like I’d been using it for years the moment I laid hands on it. The Vixen R130Sf is absolutely the perfect size for someone who needs enough aperture to light up popular deep sky objects, but doesn’t need to lug around a 12″ telescope where ever they go. This one is a true workhorse – capable of showing a huge amount of the NGC catalog and delivering lunar and planetary views without requiring dewshields, battery packs, bells, strings or whistles. It’s just a great scope that’s built to last and one meant for someone who plans on using it for years. If you think there’s a coma issue? Then don’t look at the very edge… look at those perfect sharp pinpoints in the middle. The PortaMount II is quality through and through, it’s not going to just fall apart on you and it would be oh-so-easy to adapt any number of other telescopes right to it just as easily as the R130Sf went into place with that blessed universal dovetail. Go on, accuse me of saying things I don’t mean because this is a donation… I dare you. Because I’m telling you right now that there’s a couple of my scopes that I’ve lent to friends that I’m going to offer to them for cheap. Why?

Because I’ll want that Vixen comfort back.

Check out Amazon.com for cool deals on Vixen R130Sf Newtonian Reflector Telescope.

My most heartfelt thanks to the good folks at Vixen Optics for their generous donation. Please know that your support will benefit thousands of children who come to us each year for astronomy outreach! For those of you interested in the Vixen R130Sf Newtonian Reflector Telescope and PortaMount II, please support Vixen by purchasing from any of their premier dealers, such as OPT, Woodland Hills, Smart Astronomy, Telescopes.com and Scope City. Many thanks to Mike Romine for remembering to bring a camera, and to Mark Vanderarr for being far more photogenic than myself, and to Steve Carter and Bob Kocar for helping me “test” it.

July 23, 2009December 24, 2015 by John Carl Villanueva

Alpha Particle

An alpha particle is a particle made up of two protons and two neutrons. Since this configuration is similar to that of a helium nucleus, it’s often referred to as a helium nucleus. The term is commonly used in nuclear physics, and is one of the three particles commonly emitted during a radioactive decay, i.e., alpha, beta, and gamma particles.

Alpha particles gained prominence during the early days of particle physics when scientists used them as projectiles to bombard certain targets. One of the most widely celebrated experiments that made use of alpha particles was that of Ernest Rutherford’s that led to the discovery of the atom’s structure.

Using alpha particles as projectiles and gold foils as targets, Rutherford was able to come to the conclusion that atoms were made up of very dense positively charged cores with the much lighter negatively-charged electrons orbiting around it. His conclusion was based on the observation that the trajectories of the alpha particles were slightly deviated (as expected) at most times but in rare instances bounced off like ping-pong balls thrown against a wall.

The alpha particles went through the gold foils unhindered when they passed through the large but sparsely filled region around the nucleus. However, when, during much rarer instances, they happened to collide head on or even came close to the very dense and positively charged nucleus, they were deflected at very wide angles.

Through this information, there was no other option but for Rutherford to conclude that the atom must have a very dense nucleus which is very much smaller compared to the entire atom.

In terms of atomic proportions, alpha particles are considered very massive because of the existence of the two protons and two neutrons. Furthermore, they are also positively charged due to the protons. As such, they can easily wreak havoc to most targets. That is, they have high ionization properties.

Alpha particles are released during alpha decay processes which can happen most especially to ultra-heavy nuclei like uranium, thorium, actinium, and radium. Since they’re not as fast (due mainly to their masses) as betas and gammas, they can’t travel across large distances and can be easily stopped by a piece of paper or human skin.

However, again because of their huge masses, alpha particles can be very dangerous whenever they can somehow enter the body through inhalation or ingestion. Minus that possibility, you don’t have to worry much about this heavyweight of a particle.

Universe Today has some interesting related content that you might want to read. Want to know about how the Opportunity rover got sidelined by a charged particle hit? And here’s an article about alpha radiation.

There’s more about it at NASA. Here are a couple of sources there:

Here are two episodes at Astronomy Cast that you might want to check out as well:

July 23, 2009December 24, 2015 by Tammy Plotner

IYA Live Telescope Today: Fomalhaut – Alpha Piscis Austrini

Located just south of the ecliptic plane, Piscis Austrinus was one of the original 48 constellations charted by Ptolemy, and it remains one of the 88 modern constellations adopted by the IAU. Spanning 245 square degrees of sky, it ranks 60th in size. Piscis Austrinus contains 7 mains stars in its asterism and has 21 Bayer Flamsteed designated stars within its confines. It is bordered by the constellations of Capricornus, Microscopium, Grus, Sculptor and Aquarius. Piscis Austrinus can be seen by all observers located at latitudes between +55° and -90° and is best seen at culmination during the month of October. Today the IYA “Live” Telescope was aimed at its brightest star… Wanna’ see?

Piscis Austrinus is also known as Piscis Australis – Latin for the “Southern Fish”. Prior to the 20th century, it was also known as Piscis Notius. In mythology it is said to represent the parent of Pisces. Perhaps the legend came from the Syrians who did not eat fish, but worshipped them as gods. The Greeks also kept fish ponds at their temples and one legend tells of woman who was turned into a mermaid when she threw herself into a pond in a suicide attempt. There are those who believe Pisces Austrinus is associated with the Assyrian fish god Dagon and the Babylonian god Oannes, but at least all accounts give a rather “fishy” tale!

Let’s take a look at Piscis Austrinus’ brightest star – Alpha – the “a” symbol on a star chart. Alpha Piscis Austrini is best known as Fomalhaut – the “Mouth of the Whale”. This class-A main sequence star is about 25 light years from Earth, and like Vega, has an excess of infra-red radiation which indicated a circumstellar disk. Not only does it have a disk, but it has an extrasolar planet, too… One that was photographed by the Hubble Space Telescope between 2004 and 2006 and confirmed in 2008! The Jupiter-sized planet orbits about 11 billion miles away from the parent star and takes about 872 years to make the full trip – and may very well have a ring system which dwarf’s that of Saturn’s.

As stars go, Fomalhaut is quite interesting enough on its own. In ancient times it was considered one of the four “royal” stars that marked the cardinal directions and Ptolemy gave it astrological significance as well. It is a young star, maybe around 100 to 300 million years old and part of the Castor Group of Moving Stars. The stellar association in the Castor group include stars of similar age, origin and similar velocity and include Castor, Fomalhaut, Vega, Alpha Cephei and Alphae Librae. All of these stars may have originated from the same location at some point in time which may have made them part of star cluster. In binoculars you will also notice another nearby star – TW Piscis Austrini – it is also a member of this group and may actually be a physical companion of Fomalhaut. Keep a watch on TW, though! Because as its two letter designation indicates, it is a variable star… But not just any variable. TW Piscis Austrini is a flare star! While flares can erupt periodically within a matter of hours or days with no predictable timetable, TW is also a prime candidate for harboring an Earth-like habitable zone, too!

July 23, 2009December 24, 2015 by Nancy Atkinson

Apollo Landing Sites Pose a Threat to LRO Instrument

The Laser Ranging Retroreflector experiment on the Moon. Credit: Lunar and Planetary Institute

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The recent images released by the Lunar Reconnaissance Orbiter of the Apollo landing sites are truly remarkable. But there is one instrument on board LRO that must avoid studying some of the the Apollo sites as well as other places where humans have placed spacecraft on the the lunar surface. The Lunar Orbiting Laser Altimeter (LOLA) pulses a single laser beam down to the surface to create a high-resolution global topographic map of the Moon. However, LOLA is turned off when it passes over the Apollo sites because bouncing the laser off any of the retro-reflective mirrors on experiments left by the astronauts might damage the instrument.

Don Mitchell, who owns a software consulting company and is writing a book on the Soviet Exploration of Venus, wrote about this problem on his blog, saying that if LOLA’s beam did strike the retro reflector experiment, “the light bounced back would be 1,000 times the detector damage threshold.”

LOLA Engineering model. Credit: Goddard Space Flight Center

The LOLA instrument is based on Mars Orbiter Laser Altimeter (MOLA), flown on Mars Global Surveyor and the Mercury Laser Altimeter (MLA), currently on MESSENGER. LOLA will perform the same type of work as these previous instruments, but with 3-5 times greater vertical accuracy and 14 times more measurements along the spacecraft ground track.

The Laser Ranging Retroreflector experiment was deployed on Apollo 11, 14, and 15. It consists of a series of corner-cube reflectors, which reflects an incoming light beam back in the direction it came from.

Ever since the experiments were deployed, the McDonald Observatory in Texas has beamed a laser at these mirrors and measured the round-trip of the beam. This provides accurate data on the Moon’s orbit, the rate at which the Moon is receding from Earth (currently 3.8 centimeters per year) and variations in the rotation of the Moon. These are the only Apollo experiments that are still returning data. A similar device was also included on the Soviet Union’s Lunakhod spacecraft.

David E. Smith, LOLA principal investigator confirmed that, indeed, LOLA is switched off over the Apollo and Lunakhod sites, to avoid damaging the instrument. He said the Russians have been very helpful in in providing the LOLA team the best known locations for the two Lunokhod landers. Lunokhod-2 has been located precisely and is routinely probed by lasers from Earth. Lunokhod-1 has never been found by laser, and it is not known for certain if its reflector is deployed. Smith said he and co-PI Maria Zuber have visited Moscow to consult with Russian scientists, who have shared their knowledge of the locations of their landers.

As Mitchell wrote, “While conspiracy nuts debate the reality of the Apollo landings, scientists must deal with some practical consequences of what astronauts put on the Moon.”

Sources: Don Mitchell’s Blog, email exchange with David E. Smith

Hat tip to Emily Lakdawalla on Twitter!