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Carolyn Collins Petersen

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Saturn May Have a New Moon

Tuesday April 15, 2014

Cassini Spots a New Object in Saturn's Rings

If you're out stargazing over the next few months, at some point, you will notice the planet Saturn. On these April nights, it's rising late in the evening (right now around 10 p.m. or thereabouts), so you have to stay up to find it. But, it's well worth the look. The rings alone give this planet an otherworldly and fascinating appearance.

Those of us who gaze at Saturn from our backyards aren't the only ones watching this planet. The Cassini spacecraft, which has been studying the Saturn system since 2004, has been our eyes, ears, and planetary science exploring, sending back incredible images and data.  It has sent the Huygens probe to the surface of Saturn's largest moon, Titan, returning amazing information about this weird world. Cassini has also found an ocean of salty water beneath the icy surface of the moon Enceladus, mapped the rings, and shown us the beauty of Saturn's ever-changing cloud tops. Recently, it documented the formation of a small icy object within one of the planet's outermost rings. It could be a new moon, forming from the chunks of ice that orbit Saturn and form its rings.

A possible new moon in Saturn's A ring.

A possible new moon of Saturn, discovered as part of a disturbance in Saturn's outermost A ring. Courtesy NASA/JPL-Caltech/Space Science Institute.

The object shows up in images taken with Cassini's narrow angle camera on April 15, 2013, and shows disturbances at the very edge of the A ring. One of these disturbances is an arc about 20 percent brighter than its surroundings, 750 miles (1,200 kilometers) long and 6 miles (10 kilometers) wide. Scientists also found unusual features in the usually smooth profile at the ring's edge. It's likely that the arc and its features are caused by the gravitational effects of a nearby object.

The object is not expected to grow any larger, and may even be falling apart. However, its formation process and outward movement may be a big help to planetary scientists as they seek to understand how Saturn's icy moons, including Titan and Enceladus, may have formed in ancient rings that were once much  more massive than the set we see today. It also provides insight into how Earth and other planets in our solar system may have formed and migrated away from our star, the Sun.

The object, which scientist have nicknamed Peggy, is too small to be seen in images so far. Scientists estimate it is probably no more than about a half mile (about a kilometer) in diameter. For perspective, Saturn's icy  moons range in size depending on their proximity to the planet. The more distant they are from Saturn, the bigger they are. Many of the moons and particles in the rings are made mostly of ice. Based on these facts, and other characteristics of the moons and rings, researchers recently proposed that Saturn's icy moons formed from ring particles and then moved outward, away from the planet, merging with other moons on the way. This discovery of a tiny moon, possibly as it is forming, is an important step in verifying this theory.

The more rings scientists study, the more they learn about these ephemeral (short-lived phenomena). It is possible the process of moon formation in Saturn's rings has ended with Peggy. This is because Saturn's rings are very likely too depleted to make more moons. Ring system formation (and destruction) is an exciting and incomplete story in the history of the solar system.  The current theory is that Saturn's rings were once much more massive, and had enough material to create many moons as ring particles collided.

The Cassini mission has been a very successful exploration of the Saturn system. As such, it has been extended several times. Its current official mission, now known as the Cassini Solstice Mission, was last extended in 2010 for several more years and will allow the spacecraft to study the system up through Saturn's summer solstice in May 2017.  This will mark one complete set of seasons on Saturn that the mission will have studied, giving planetary scientists an incredible amount of information about this planet, its moons, and rings.

 

Watch the Moon Turn Red

Friday April 11, 2014

simulated view of lunar eclipse

How the April 14-15, 2014 lunar eclipse could look during totality. The Moon will be near the bright star Spica. Created by Carolyn Collins Petersen using Stellarium open source software. Click image for a larger version.)

Experience a Total Lunar Eclipse!

On April 15th, in the wee hours of the morning, you have a chance to see one of nature's most awe-inspiring events: a total lunar eclipse. People are referring to this one as a Blood Moon because at totality (the darkest part of the eclipse), the Moon will appear a deep red color. Observers across the Americas, and parts of the Pacific will able to witness it beginning late Monday night April 14 into the early morning of April 15th. (For a complete list of what locations on Earth will see this eclipse, check out NASA's Eclipse Web page.)

What You Will See

So, what is a lunar eclipse? These rare events happen at Full Moon, when the Moon moves into Earth's shadow as it orbits our planet. The entire eclipse takes almost 6 hours (5 hours 43 minutes). First, it slips into the penumbra at the western edge of the shadow. At first, you won't notice much because the Moon is still quite bright. Then, about an hour later, the Moon will begin entering the umbra, the darkest part of Earth's shadow. This is when you will start to notice the Moon slowly taking on color -- anywhere from a ruddy brown to a coppery red.  The Moon will spend just over an hour (1 hour 17 minutes) in the umbra. Then it will slowly move out into the eastern part of the penumbra, and finally exit Earth's shadow completely.

When Should I Look?

Here's a short timeline of events. Times are approximate.

The eclipse begins at 4:53 AM UT (April 15) 12:53 AM EDT, 11:53 AM CDT (April 14th),  10:53 PM MDT, 9:53 PM PDT, 6:53 PM Hawai'i time.

Totality begins at 7:08 AM UT (April 15), 3:08 AM EDT, 2:08 AM CDT, 1:08 AM MDT, 12:08 AM PDT, 9:08 PM Hawai'i (April 14)

Totality ends at 8:23 AM UT (April 15), 4:23 AM EDT, 3:23 AM CDT, 2:23 AM MDT, 1:23 AM PDT, 10:23 PM Hawai'i (April 14)

Eclipse ends at 10:35 AM UT (April 15), 6:36 AM EDT (below horizon), 5:35 AM CDT, 4:35 AM MDT, 3:35 AM PDT, 12:35 AM Hawai'i

 

Lunar eclipse timeline

A timeline of the April 14-15, 2014 lunar eclipse, based on data from NASA. Click image for a larger version.

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A Black Hole Cannibal at the Milky Way’s Heart

Monday April 7, 2014

How Black Holes Grow

Gas cloud headed toward the black hole in Milky Way Galaxy's heart.

For the past few years, astronomers have been watching with great interest as a cloud of gas called G2 gets ever closer to the black hole at the center of the Milky Way Galaxy. The cloud (shown in the image at left) is headed directly into Sagittarius A* (Sgr A* for short) and will get caught up in the accretion disk of material surrounding and feeding into our black hole. The collision is already starting to occur, although the largest mass of the cloud has not yet arrived at the disk. But, the outer edges are starting to feel the pull of the black hole and that is providing a unique opportunity for astronomers to watch as a black hole swallows up material.

It could be quite an interesting sight. One common view of  black holes and how they consume nearby objects suggests that as a cloud or other object moves through the accretion disk toward the black hole, it gets stretched out. This is because the gravity of the black hole pulls on the closest parts of the object first. One popular illustration shows an astronaut going feet-first into the black hole and getting stretched thinner and thinner. That process, nicknamed "spaghettification", eventually tears the object apart. So, observers will be on the lookout for evidence as the cloud begins to disintegrate under the black hole's voracious gravitational pull.

Astronomers can already tell that the cloud's edges are starting to shred as they get close to the accretion disk. In addition, temperatures in the cloud are rising. For that reason, the Swift X-Ray satellite and the Chandra X-Ray Observatory are both monitoring the Sgr A* region, to catch the rise in x-ray emissions as the cloud is heated up during its its death march into the black hole.

Read More...

Ten Great Sky Sights for April 2014

Friday April 4, 2014

I've been a stargazer since I was a child, and continue to go out and explore the sky when the conditions are right. Skygazing is an easy pastime, and a rewarding one. Want to check out the planets Mars, Jupiter and Saturn? See the Moon turn red? Experience a meteor shower? They're all available on April evenings after the sky gets dark. You don't need any special equipment, but if you do have binoculars or a small telescope, use them. Here's a list of ten great sky sights for April for you to search out. Go to About.com's star chart page to make a sky map for your location and let's do some stargazing!

  1. Jupiter. The famed astronomer Galileo Galilei had only a small telescope to study this giant planet, but the four moons he saw changed our view of the solar system. These small worlds, the Galilean satellites are easy to spot with a good pair of binoculars and look even better through a telescope. Jupiter is the brilliant shining dot in the constellation Gemini, the Twins.
  2. Mars. The Red Planet is easy to spot with the naked eye this month. Just look for a brilliant reddish dot in the constellation Virgo late in the evening, well above the eastern horizon. It's not too far from the bright star Spica.If you happen to have a good-sized telescope, you might be able to make out some surface markings on Mars.
  3. The Moon. Want a great observing target throughout the month? Check out the Moon. The dark areas on heavily cratered surface are called "maria", which is Latin for "seas". You will also see some bright areas marked by splashy-looking rays. These are craters and the rays are where the material gouged out by long-ago impacts spread out across the surface.
  4. A Total Lunar Eclipse. On the evening of April 14th into the morning of the 15th, watch as the Moon passes through Earth's shadow in a total lunar eclipse.  It will gradually get dark as it moves through the penumbra. Later, the Moon will pass into the umbra - the darkest part of Earth's shadow. It will look darker and probably turn a coppery red color. The eclipse will be visible throughout North and South America, and parts of the lower Pacific basin, including Australia. Read More...

Penumbral Lunar Eclipse ... Oct 18, 2013

Friday October 18, 2013

The Moon will be full this evening.  A full moon occurs approximately once every calendar month, when the Earth is positioned between the Sun and the Moon, so that observers located on the unlit side of the Earth are directly facing the fully-lighted face of the Moon.

At this time, the Moon is normally near it's brightest as seen from Earth; however, this evening at around 7:30 PM EDT, a portion of the Moon will darken noticeably as it enters and passes through the shadow of the Earth.  This is known as a lunar eclipse.  This event may already be in-progress at moonrise if you live in the US.

Lunar eclipses don't occur every month because the Sun-Earth-Moon alignment is rarely along a straight line.  When they do occur, eclipses vary in degree from "partial" (where the Moon is only partly in the Earth's shadow) to "full", where the Moon is entirely darkened by the Earth's shadow.  This evening's lunar eclipse is of the "partial" variety, and is more specifically known as a "Penumbral Lunar Eclipse" because only the Moon's southern edge passes through the outer edge of the Earth's shadow.

You can learn more about tonight's eclipse on the NASA web site.

This will be the last lunar eclipse of the year 2013.  Enjoy!!

 

by James Toothman

Moon-Venus Conjunction

Tuesday September 10, 2013

Moon and Venus in close conjunction on Sunday September 8th, 2013.

View Full-Size Image

 

Sunday September 8th, 2013 photo of the Moon and Venus appearing together in close proximity in the twilight sky over New Jersey.  This apparent alignment in the sky as observed from Earth is known as a conjunction. Image taken using Canon EOS Rebel T2i with Sigma 18x250mm zoom lens, 1/8th second exposure.

by James Toothman

3-D Licious

Friday July 12, 2013

Every Trekkie knows that slightly glitchy food replicators will be commonplace by the 24th century, providing personalized meal service on-demand to the crew of every star ship. Menu choices then will be limitless! But how do we get there?

Rewind 300 years or so. To kick things off, NASA is giving a Texas-based engineering firm 6 months and 125 million dollars to learn how to make ... pizza.

Well, actually not just pizza. Though pizza is expected to be an early prototype, research contractor SMRC (Systems and Materials Research Corporation - Austin, TX) proposes to design machines that can serve up a wide variety of nutritious, if not delicious, foods from just a handful of raw ingredients. They've imagined lofty goals of widespread commercialization, possibly even the promise of averting a food war or putting an end to world hunger. Achieving success will depend upon radically extending the development of existing "additive manufacturing" technologies into the realm of cuisine.

More widely known as "3-D printing", additive manufacturing is so named because it quite literally builds 3-D objects by repeatedly depositing thin layers of material, adding one upon another until the desired final shape is complete. These 3-D printing devices function a lot like your everyday 2-D ink jet printer, except that they make multiple passes over the same surface. To print a pizza, the device follows a digital blueprint. The blueprint becomes the recipe. Instead of dispensing cyan, magenta, yellow, and black dyes onto paper, SMRC will blend sugars, starch, oils & fats, proteins, and water to concoct something hopefully resembling dough and cheese.

Historically, space food might generously be described as minimalistic. During the early years of space travel, size and weight were the primary considerations. It simply wasn't feasible to carry "real" foods, and so the earliest astronauts made do with freeze-dried chunks of protein and toothpaste-like tubes of goo.

As the space program progressed and spacecraft grew larger, so too did the menus. But these larger spacecraft also accommodated more astronauts, and for longer durations, raising the need to efficiently store even more food (and waste) for longer periods.

Even recently, Shuttle astronauts needed to pre-plan their meals months in advance of each space flight, under the careful guidance of a trained nutritionalist. The list of available menu items was, by comparison, surprisingly extensive ... basically the same ordinary grocery store foods that we all enjoy. However, only a small quantity of fresh breads, fruits, and vegetables, could be carried on each journey; most provisions were still specially prepared and packaged to reduce bulk, increase shelf life, and make eating them manageable in the microgravity of space.

Today, with an eye toward very long duration space flights to Mars, shelf-life has become the key factor. According to NASA, food stores for a manned mission to Mars would need a minimum shelf-life of 3-5 years, but the current generation of "rehydratable" and "thermostabilized" space food degrades over time and does not meet these requirements. SMRC reportedly hopes that the raw ingredients for their printable system could remain edible and nutritious for upwards of 30 years.

Is 3-D printed space food the way to go? I for one can't imagine planning all my meals years in advance, so being able to offer our astronauts countless spontaneous combinations of synthesized dishes would certainly seem to me to offer an advantage over the current method of recycling the same pre-planned menus week after week. Will synthesized food taste good? Taste necessarily may be only a secondary consideration for NASA, but one they will surely do their best to address ... a hungry astronaut is not a happy astronaut. Perhaps one day soon NASA can again honor Gene Roddenberry, visionary creator of "Star Trek", by naming their first tasty 3-Dessert after him: "Rodden-Berry Pie".

3-D printing is very trendy, sometimes controversial, and just now in it's infancy. If NASA can make printable food viable for space travel then it might just be around the corner for the rest of us too, joining the ranks of talking supercomputers, handheld portable communicators, and ion propulsion as fantasy-turned-fact. And yes, $125 million for pizza may sound expensive, but remember it will come with as many toppings as the astronauts like AND fast, free delivery to anywhere within low-Earth orbit in 30 minutes or less.

by James Toothman

Could Warp Drive One Day Be Reality?

Sunday September 30, 2012

It has captured the imaginations of science fiction fans the world over - the possibility of traveling to distant worlds in the blink of an eye - but it has remained little more than fantasy.

We currently occupy a time where a significant technological deficit prevents us from considering such propositions, but that does not mean that interstellar travel could not one day become reality. And, it seems, that we have taken one more step toward that goal.

In order to get around the cosmic speed limit, the concept of warp drive was introduced. Such a scenario would actually cause space-time around a space craft to expand and contract, creating a cosmic wave, if you will, upon which the ship would ride.

While Einstein's equations preclude mass from traveling at speeds greater than that of light, space-time itself has no known limitations. So creating a bubble of space-time that moves faster than the speed of light that carries a space ship along with it - that, in effect is stationary in reference to the space-time bubble - is a clever end around the limitations of physics.

However, there has always been a problem with this hypothetical warp drive: Energy.

Even if we possessed the technological knowledge to effectively warp space-time around an entire ship, which we don't, the energy needed was always thought to be prohibitive. However, a new design suggests that there may be ways to dramatically reduce the energy needed.

While there is still a long way to go - these new designs would still require roughly the entire electricity output for the entire world for an entire year just to get the thing going - these strides point to a future where, with more study, the idea of warp drive may no move from being highly improbable to possible.

Image Credit: Harold White/NASA

Video of the Curiosity Descent and Landing

Friday September 14, 2012

Several weeks ago the internet watched in awe as the Mars rover Curiosity completed its journey to the surface of the red planet.

Now, as it begins the next phase of its mission, to search out evidence of here life may have formed, if at all, video is starting to emerge of its plunge through the atmosphere.

Many people have taken to constructing these videos, using NASA/JPL data to construct brilliant high-def movies. But a stumbled across one on Youtube that I particularly liked, so thought I would share. Enjoy!

Passing of Neil Armstrong

Sunday August 26, 2012

The world lost a great hero on Saturday. Astronaut Neil Armstrong passed away at the age of 82.

His death came somewhat suddenly, arising from complications with a cardiovascular procedure.

Armstrong was a quiet, private man, who was content to live outside of the spotlight after his historic Moon landing. But it was he and his fellow astronauts that inspired a nation, and indeed the world, to dream that mankind was capable of making the impossible, well, possible.

Stay tuned to this space; I'll have more on Armstrong, including a piece on how it was the likes of him who inspired a nation to greatness.

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