Saturday, May 14, 2011

Astronomy News Update 5/14/11

Originally, a couple of these stories were to have articles of their own on my blog. The whole Blogger going down thing messed up my flow, and since I am limited on what I can post in a day (I try to keep it to one post), I decided to lump them together with some other cool astronomy news. So, I unofficially bring back a 'Caturday News Round-Up!' These are some of the best stories in the astronomical community from the past week or so. Check them out:

Squids in Space: On Space Shuttle Endeavour's last flight, it will be carrying some very special passengers: baby squid. Not just any squid either, they are glowing bobtail squid. They carry a bacteria called Vibrio fisheri which the squid use to generate light to ensure they do not generate shadows that predators might see. The goal of this experience is to build an understand of how "good" bacteria behave in microgravity.

Cross-section of the interior of Jupiter's moon Io. (NASA/JPL/University of Michigan/UCLA)

Magma Ocean Beneath Io's Surface: A new data analysis from NASA's Galileo spacecraft reveals a huge magma ocean beneath the surface of Jupiter's volcanic moon Io. This analysis shows the source of the most volcanically active body in the solar system. Io produces about 100 times more lava per year than all the volcanoes on Earth. The Galileo probe began orbiting Jupiter in the late 1990s, including flybys of Io and other moons, before it was intentionally sent into Jupiter's atmosphere in 2003.

Super-Earth Gliese 581d is in the 'Habitable Zone': While in recent years the idea of a 'habitable zone' has fluctuated in scope, a team of French researchers have come to the conclusion that Gliese 581d could reside in its star's habitable zone. The Gliese 581 system has been a popular place of study as of late because of the possibility of habitable planets, including 581g which would by located well in the habitable zone but existence is debated. 581d is a super-Earth sized planet on the edge of the habitable zone, but a suitable carbon dioxide atmosphere would allow liquid water. More direct observations are beyond the capabilities of current telescopes, but Gliese 581 would a good candidate for future instruments.

Dawn's first glimpse of Vesta - Processed. (NASA/JPL-Caltech/UCLA/MPS/DLR/IDA)

Dawn's First Image of Asteroid Vesta: NASA's Dawn spacecraft has taken its first image of Vesta, the second largest object in the asteroid belt. It is set to enter orbit around Vesta on July 16. The image will help fine-tune navigation during it's approach. After Dawn completes its mission at Vesta, it will leave orbit and head to the largest object in the asteroid belt, the dwarf planet Ceres.

Bacteria Grow Under 400,000 Times Earth's Gravity: This biological finding would expand the definition of the habitable zone once again. These bacteria grew under the pressure of 400,000 times Earth's gravity, which would expand where life might be found. This "hypergravity" is usually found in massive stars or the shock waves of supernovas, and is recreated on Earth using an ultracentrifuge. Two of the species tested were E. coli, a common gut bacteria, and Paracoccus denitrificans, a common soil bacteria.

Friday, May 13, 2011

Blogger Annoyance & Moon Photos

So, as a few of your may have noticed blogger has been an annoyance, being down most of the past two days. I can understand that, updates need to be done, but something seems to have gone terribly wrong with the entire thing.

As it stands now, I lost my Endeavour Launch Update article, I hope that it may be returned... If not, know that Space Shuttle Endeavour is set to have it's final launch at 8:56 a.m. EDT on Monday, May 16. Everything is on course and repairs to the Shuttle's heater system that caused the initial delay have been fixed. After this flight it will go into retirement and be displayed at the California Science Center.

The launch of the Space Shuttle Atlantis has been pushed back to mid-July.

The argument can be made of why retire the shuttles and so forth. Their need for retirement is made obvious by this delay and the previous delays and the all but certain delay of Atlantis. These shuttles are falling apart, they are old, they need replacement. This process was started under the Bush administration, but even in the Clinton administration doubts were beginning to be raised.

As for why there isn't a replacement on hand, it is an unfortunate bureaucratic side effect. There was a plan, the Constellation program that was to design and build new Ares rockets and the Orion space capsule (akin to the Apollo capsule, but larger and more up to date). The program was severely over budget and bogged down by bureaucratic red tape and political pressure. One of the first things the Obama administration pushed was a complete overhaul which rightly cancelled the Constellation program. But rather than throw the baby out with the bath water, the Orion capsule is still being developed and the work on the Ares rockets is being used in further rocket developments. All in all, it's sad that things got off track, but we are hopefully on the right track right now.

So with that cleared up, I have been busy with blogger being down. First, I have been elected to the Board of Directors for the Harford Country Astronomical Society. After only a short year of being with them I have thoroughly enjoyed my experience with them, as I am sure they appreciate my help. Now I get to have some input on the direction of the club as far as outreach events and observing and astrophotography. I am pretty excited and hope to do good for the club, even though every organization has its internal issues and debates.

Next, earlier this week I finally got the piece for my telescope that allowed my camera to be in a position so that it would take focused shots. You may remember about a month ago, I published my first set of (blurry) pictures along with a video of the Moon. Well, I got a new video (below) and a new moon shot(above), as well as a shot of Saturn. Thinks look a lot better being able to focus correctly. Plus I figured some things out with Windows Live Movie Maker that made the video better.

I still have some things to learn. The moon is a fairly easy target, but Saturn was tricky. My telescope doesn't track to well either. I pretty much had to take a video of Saturn and pluck out the best frame for the image I have below. I also need to find the right camera settings for taking images of planets, as it was hard to just get Saturn to resolve an image. (The blue has is from atmosphere, it was slightly cloudy.)

I think that about wraps things up. I am hoping to get better and this and share more of my own images with you in future. The HCAS observatory is off limits due to construction of the next few months, so I probably won't have much in the way of deep sky objects to share, so hopefully this will do.

With my schedule out of whack from Blogger issues, I am trying to consider what I am going to be doing over the next week. Monday will most definitely be devoted to the hopeful shuttle launch, Tuesday another Astro-Lesson, and Wednesday or Thursday will hopefully see my 100th blog post!

Tuesday, May 10, 2011

Astro-Lesson: The Star Life Cycle

This week's topic kinda picks up from last weeks topic, the Sun. From our short and limited view of the cosmos, we have been able to discern something amazing, the life cycles of stars. It turns out stars have a birth, then long lives of constant work converting hydrogen to helium and other elements, and then they die, either by withering away or massive violent explosion.

Art of the life of a Sun-like star.
 There is a significant reason why knowing this is important. A star can last for BILLIONS -- or even TRILLIONS!-- of years, and yet humans have only been around for about 200,000 years, but a brief moment of any star's life. But if it isn't possible for us to observe the entire life span of a star, how have we figured it out? Well, there are lots of stars out there, of all different ages that show features that relate to other stars, this allows us to work with something to make a model out of.

The best analogy I can provide is this: Imagine being in the woods, deep in a seemingly infinite forest that stretches to the horizon. You are surrounded by trees, while you are stuck to a tree yourself, the only one that you can see up close. Your tree appears to be a sturdy adult tree, analogous to our Sun. Looking out into the forest you see a variety of trees; without knowing the life cycle of the tree, they may not seem otherwise connected. You have seeds on the ground, saplings sprouting up, small trees, big trees, really big trees, and rotting logs on the ground.

Sagittarius Star Field - Our Forest.

This analogy can go further; those rotting logs provide subsistence for the next generations of trees, much like supernovae provide matter for new stars. And occasionally you might hear the crash in the distance of a tree falling, much like a supernovae or gamma ray burst going off. And what lies beyond the horizon remains a mystery since you are tied to one tree, just like massive size of the Universe.

Now the trick is, you have only a minute to gaze out into this forest to try discern what is what. And that brings the analogy home with what humanity has been able to accomplish. In our brief glimpse, we have been able to identify saplings, healthy full-grown trees, various species of trees, and dying or dead trees, of course in stellar terms. So lets now look at a few of these stages of the life of a star.

Concept art of the birth of a star in a molecular cloud. (NASA)

Protostar: This is where a star begins to form. A molecular cloud or nebula of dust and gas that starts "clumping" together. As the atoms gather, their gravitational attraction pulls in more atoms, making a larger "clump". This process is known as accretion. Lots of reactions happen inside an unstable protostar, which can have influences on a possible planetary system. Once the protostar achieves and maintains equilibrium, balance between gravity pulling atoms toward the center and gas pressure pushing heat and light away from the center, it becomes a star.

Not all stars are born equal! Stars are born into a variety of sizes and colors, depending on their composition, mass of formation nebula, and temperature. These stars lead vary different lives, of varying length, and die in dramatically different ways.

Small-Medium Stars: The overwhelming majority of stars, at least in the Milky Way, fall into this category, including the Sun, up to 1.5 times the mass of the Sun. These are amongst the longest living stars, the Sun is predicted to last 14 billion years, and it is roughly 4.6 Billion years old now. Smaller stars than the Sun can last billions of years longer. The smaller a star is, the longer it will live.

Hertzsprung–Russell diagram, commonly used to classify stars.

The majority of the life of a star will take place during a phase called the main sequence. This is when the star fuses hydrogen to produce helium in high-temperature and high-pressure reactions near the core.

After a small star like the Sun burns up all of its hydrogen, it leaves the main sequence. It begins to burn helium instead, converting helium atoms into carbon. The star loses its previous equilibrium, so in order to maintain it and keep cool, the star 'puffs out.' The star is now called a red giant, and is the first step in old age. The Sun may expand out to roughly the distance of Earth, 250 times its current size!

A red giant is very unstable, and may expand and contract, these stars are known as variable stars. This period if very short, only lasting a couple million years over the billions of years in a star's life. Soon the helium will burn up and and the star will again change as it switches to the last phase of fusion -- carbon burning.

The Cat's Eye Nebula is a planetary nebula. (NASA)

When a star switches to fusing carbon, the core contracts inward, down to about the size of the Earth. The outer layers of a star are blown off into space into a planetary nebula. Often beautiful to see from Earth, these are the dying throws of a star. The star becomes a white dwarf, densely packed, but not massive enough to become an neutron star or black hole. A white dwarf burns slowly and will gradually fade into a black dwarf, a cold dark mass. However, the Universe is not old enough for any black dwarf stars to exist yet.

A VERY Giant Star (the biggest known)

Huge and Giant Stars: These are stars much more massive then the Sun, with drastically shorter lifetimes. There are two classifications here based on the predicted end results of the star. Here we will call a star that is between 1.5 to 3 times the mass of the Sun a huge star; and a star greater than 3 times the mass of the Sun will be a giant star.

These stars spend a relatively brief period on the main sequence, since they are larger and burn hotter, they burn their hydrogen quickly. When they begin helium burning, they enter a special sort of phase, they become red supergiants, the largest known stars in the Universe by volume.

The onion-like layers of a massive star just before core collapse. (Not to scale.)

These stars are so large, they begin to fuse elements in an onion like structure near the end of their lives. Fusion of elements all the way up to iron on the periodic table is possible before a core collapse. The core of the star essentially is unable to support its weight against gravity. A massive explosion then occurs, a supernova, which violently blasts the upper layers of the star into space, leaving behind the core.

One of two things happens to the core: If it was a huge star, the core becomes a neutron star. If it was a giant star, it becomes a black hole. You can read more about black holes and neutron stars in one of my older articles.

The Crab Nebula, the remains of a supernova first observed around 1050 AD.

Tiny Stars: A special case in stellar physics, these are stars smaller then 0.5 times the mass of the Sun. These stars never fuse helium into higher elements, they do not have the mass to exert the pressure on the core. They are known as red dwarfs, like Proxima Centuri. These stars can exist on the main sequence for up to trillions of years and have life spans longer then when the Universe is predicted to end. They may eventually fade to white dwarfs, but there is no real way of knowing.

That accounts for an overview of star life cycles. I hope this helps you to understand some of the differences between stars and their end results. Astronomers were able to piece this together looking at the clues that the Universe has given us, from our brief glimpse. We have been able to determine the amazing course of existence for the very things that gave us life.

Monday, May 9, 2011

Life on Ceres

I like to look at my stats and see what people are searching for when they come across my blog. A while ago I got a hit from a search for 'Life on Ceres,' and ever since then I have been considering writing a post about it. So this is for you, person out there looking for information about life on Ceres, and hopefully other readers will enjoy this as well.

I had previously glossed over Ceres in my Asteroids Astro-Lesson. Ceres is the largest object in the asteroid belt, and recently got reclassified to a dwarf planet. It is also the smallest known dwarf planet, Pluto (the former smallest planet) is 14 times more massive. And yet Ceres comprises about 25% of the asteroid belt's mass. Ceres is large enough to shape itself into a sphere, at about 580 miles (930 kilometers) across.

But aside from being a unique and astounding body in the asteroid belt, Ceres may have large amounts of water buried under the crust. Astronomers have suggested this because the ex-asteroid's density is less then that of the Earth's crust, because the surface bears spectral evidence of water-bearing minerals. If 25% of Ceres was composed of water, it would have more than all the fresh water on Earth.

The possible internal structure for Ceres. (NASA)

The majority of the water would be ice, forming a mantle around a rocky inner core, with a dusty crust above. It is currently unknown if liquid water exists on Ceres, but a few astronomers suspect there could be oceans. These oceans could be heated by hydrothermal vents and provide a thriving ecology of basic lifeforms.

The problem with this scenario though, is that it is not clear what would keep the proposed oceans in a liquid state. There is no significant tectonic activity (nor enough mass to sustain a long-term molten core) and no significant tidal friction (like with Europa orbiting Jupiter). Although the idea has some merit for consideration, and provides interesting research. We will have to wait until the Dawn spacecraft arrives in 2015 for any definitive answers.

Now, this is where the idea gets a little fun and funky. Supposing Ceres did have a molten core when it and the rest of the Solar System were young, it could have heated an ocean and produced early lifeforms. Well, we know that early Ceres had an active period of bombardment, where meteorites and smaller asteroids impacted and knocked small chunks off. In fact, there is an entire family of asteroids designated C-type because they share similarities with Ceres and many are thought to originate from there. They also happen to be the most common type of asteroid, carbonaceous asteroids.

What I am getting at here is the idea of panspermia, that life in the Universe can start at one place and be transported to others by meteoroids, asteroids, and comets. Ceres has a low escape velocity, so it is not improbably that any early life forms would be kicked off by an impact. That life could have then been transported to Earth, and we could be the descendants.

This is just conjecture. I should put that as a warning, that there is no solid evidence for this hypothesis, but it exists and it is a tantalizing one to discuss. And it is not wholly impossible, but we really don't know. At least not until we find some body whizzing around the Solar System carrying archaic lifeforms most likely in a dormant state. And even if a lifeform made it to Earth, there's no certainty that it survived, life could have already arisen on Earth and devastated the visitor.

The Earth seems to have perfect conditions for life, and must have had sufficient starting conditions. If life was so well at taking hold here, we could it not be formed here in the first place? Then again, maybe there weren't sufficient conditions to start life. Scientifically speaking, there is no clear definition of what caused life to spark into existence on Earth, and panspermia has been a way to address that. But it still neglects the fact that life would have had to have started somewhere at some point in time.

As we get better at understanding biology and Earth's history, this answer is getting clearer. It is now possible, with the right chemical mixtures that relates to the known early atmosphere of the Earth, to generate complex amino acids and other biological components. I suspect we are really only a few years short of understanding the sparking event that unleashed life on Earth, or at least the origin of life somewhere in the Universe if it was brought to Earth.

Sunday, May 8, 2011

Sunshine Award

I wasn't considering on caving into one of these award things. They seem more like chain e-mails then actual awards. Though I guess it is a sign of appreciation from the person who passes it on to you, that they like what you have to say.

Kicking Rocks bestowed upon me the Sunshine Award.

I kinda like the name of the award, since it deals with a celestial body (the Sun). Though backtracking it shows that it originated on some fashion blogs, but whatever, I can deal. Also, check out Kicking Rocks' blog about him rising up in the theatrical world.

The rules for this award are:
  1. Thank the person who gave you this award and link back to them in your post.
  2. Tell us some things about yourself.
  3. Nominate 10 bloggers.
  4. Contact these bloggers and let them know they have received this award.
Some things about myself:
- Yes, I really do have Bachelors Degree in Astronomy, despite this I think I am horrible at Calculus and Physics.
- I love talking to people about astronomy, space, astrobiology, and the future in general. I am a bit optimistic despite thinking that sometimes the people in charge aren't making the best decisions.
- I have a fascination with government and politics, enough so that I minored in International Politics, though I consider more of a hobby. Most people might think the other way, politics as a job and astronomy as a hobby.
- I am left handed.

My 10 victims nominations:
  1. What I learned today is... 
  2. I Kneed A Break!
  3. nyfinancestudent
  4. Bar Science
  5. Teen Book Reviewer
  6. No Really, You Can Eat It!
  7. My Own Private Idaho (like he needs another award for his stash)
  8. As A Man Thinketh, So He Becomes
  9. Mount Aenos
  10. Chocotaster

    Happy Mother's Day

    Seriously, go give her a call, or a hug, or take her out to dinner. Unless you are a mom, then I hope you have a swell day.

    On a side note, my presentation when pretty well last night. The youth group seemed to enjoy it, they were mostly in high schools, a couple in middle school. They were pretty smart too, and I always enjoy talking with a smart group of kids, it always leads to an interesting dialogue. And when it comes to alien life, they have some pretty amazing ideas.

    But as amazing as some of those ideas are, I have to remind them the importance of science and needing factual evidence. Some of them were even smart enough to talk about shadow biomes: life that may exist on Earth, but we don't recognize as life because it doesn't constitute the classical idea of what is alive. Sure they are a fun idea to think about, but when looking for life in the Universe, it's going to be very hard to find them if we can't identify shadow biomes on the Earth. No, life seems more acclimated to needing water and external energy and the way it thrives here. And looking for Earth-like environments will be be the best indicators of life, mostly because those environments stand out so clearly from the alternatives.

    It may also be that the majority of life lives in subsurface oceans of icy bodies. We now know of a number of moons with subsurface oceans, including Europa, Titan, Ganymede, Enceladus. And there probably are more. In fact, tomorrow I am planning to address that idea on the asteroid/dwarf planet Ceres. But these environments would have a hint of Earth-like influence, the would have water and an energy source (usually tidal heating caused by the friction of orbiting a large planet, or internal heat and radioactivity).

    Life is an amazing thing to talk about, and I enjoy reflecting on these presentations after I give them. And I thought I'd just share a bit of that internal thought process. Plus, everyone alive owes it to their mother, so that's always relevant and something to be thankful for.

    Another thing, I am thinking about entering the world of podcasting! Specifically the 365 Days of Astronomy podcast. Their goal is to provide a different 5-10 minutes podcast everyday from anyone interested in talking about an astronomy related topic. They vary from the professional to the amateur, both in astronomy knowledge and in podcast recording quality. I have listened to a few and they are quite amazing, but they are lacking on volunteers to fill up days. Anyways, anyone is capably of signing up and doing a podcast. There's no commitment to how many I would have to do, but it can't be more often then once a month with them.