I've been having a little bit of a hard time getting my head around some of the concepts in the life of a star so I figured I'd watch a few videos about it.
It was actually pretty helpful. I think the only part I was really having trouble with was understanding the shift from hydrogen to helium fusion. I get it better now that I've seen some visual models of it. It was aslo cool to see some images of planetary nebulae which are pretty bad ass.
I think this one was my favorite
The second video I watched (http://www.youtube.com/watch?feature=player_embedded&v=mzE7VZMT1z8) was pretty ridiculous. It covered pretty much the same exact material but in twice the time because it needed to do things like show an image of someone skiing or climbing a rock every time it mentioned gravity. For some reason it's creators also felt that in order to understand a galaxy filled with stars it needed to show us Las Vegas. I'm still unclear on the connection here.
The one cool thing it did talk about was the "Pillars of Creation" I'm going to look into those thing some more.
Just finished reading the graphic novel Logicomix about Bertrand Russel and the search for truth in logic. It was a decent comic. In truth they made a bit too much of an effort to make it accessible. They left out most of the math and technical jargon and tried to make it a story about people. By doing this I didn't feel like I could make a connection to any of their breakthroughs.
It didn't have anything specifically to do with Astronomy but it did help me come to terms with the idea mathematics as a tool for modeling the universe. I've always bristled a little bit at the idea that something we can't observe is true because the math works. Now that we've seen so many cosmic things that where described first by mathematics I'm a little more comfortable with it but I can't say I understand it. I could never accept the idea of axioms. If these are the foundation of math and logic and we are expected to believe them a priori, doesn't this require a sort of faith that logic would naturally find repellant.
This book didn't really clear up all that but it did make me feel happy that other very smart people are worried about the same thing. The book has Russel say that he's "written a 365 page book that proved that 1 + 1 = 2". I'll never read this book, apparently very few have, but I feel a little better knowing someone wrote it.
This galaxy is called M81 and it's one of the brightest galaxies in our sky.
The accompanying information was mostly about the little section up top that doesn't appear to be behaving the same way as the rest of the galaxy. It's called "Arp's Loop".
What was most interesting to me looking at this image was my reaction to it. I've seen images of galaxies millions of times throughout my life and never once thought about why they look the way they do. Looking at it now I know why the core is bright and why it's shaped the way it is. I know what's happening in the arms and in the core. These are thing I never thought of before. It's odd to me the things we take for granted.
It's about a meteorite that could have possibly come from mercury... although it turns out it probably didn't.
I guess it has a similar chemical makeup as Mercury. It's very low in iron which was one of the things that ruled out it coming from Mars or simply being an Earth rock.
Furthermore, it turns out that this rock has the same magnetic field as Mercury. I'm not exactly what that means but it seems pretty far out. I should do some reading on magnetic fields.
The one chink in this theory is that the meteorite is extremely old. So old that it predates Mercury being solid enough to create such rocks. The current theory is that it actually comes from the asteroid belt.
Either way this is apparently a very fascinating meteorite. There's a great slide show of a bunch of other meteorites on the page linked above. It includes a one from Mars, one from the moon, and one that's actually the oldest rock ever found. It was formed in the gas cloud that used to surround the sun!
It never occurred to me that meteorites could be from other planets. I
always assumed they where just free floating rocks in space. Now that
we're learning about how all this works it makes much more sense that more relatively large rocks would be formed on other planets than that they would form on their own in space.
Just checked out the Bad Astronomer blog that was suggested as an option for the website review. Having taken a closer look at it now I kinda wish I'd chosen to do a review of it. This guy's writing is so much more accessible to me than the websites I did review.
I read three of his entries. One was on the above video of silly putty, which had been mixed with iron oxide, "eating" a magnet. It's a pretty cool video and the blog's author Phil Plait explains some of it's scientific implications well. Really though I just kept thinking it would be a cool thing to do with the high school kids I tutor.
The second article was about the difference in the nights sky in the southern hemisphere. Not doing much star gazing myself I didn't find this one all that interesting.
The third one though was pretty intersting. This was about a NASA mission to bring an asteroid close enough to the earth that we can study it. Plait spent quite a bit of time talking about this one. He discussed how it could be done, why it should be done, and what the obstacles are. He included the far out drawing below of one of the capture options. If I understand it correctly this will match the movements of the asteroid pull it into it's large bag thing, close the bag then make constant adjustments until the asteroid settles down.
Plait's primary conclusion was that, although this was an incredibly cool idea, it might not really be feasible.
His skepticism was based on a few factors but primarily it came down to him not believing NASA had much of a plan or the money to do it. They'd recently announced that the white house will give $100 million dollars to this project. Not much considering how much it will cost.
A couple things that caught my eye while reading this this where
1) It's really hard to see small things in space like astroids.
2) Plait seems to think that the best option to get people up to actually look at this astroid if we get it near us is SpaceX, the privately owned space program. That's pretty amazing.
3)All this stuff is so incredibly expensive. It must be surreal to be an astronaut and know that a country is spending millions of dollars on your existence every day your up there.
Last night I had some friends over for dinner. One of them was telling me that he'd recently become curious about Astronomy and had ordered a book online that he was very disappointed in. I told him I was taking this class and we spent a good while trying to talk about concepts that where still pretty fuzzy to both of us. Of coarse the the concepts that really caught everyone's imagination where Dark Matter and Dark Energy.
To tell the truth I did a pretty bad job explaining them and my friends seemed pretty skeptical. It was very hard for them to buy into the idea of these things as both real things and sort of place holder terms for phenomenon we're pretty sure exists but don't know anything about. The more they drank the more they liked to say "The dark matter is all around us" in an ominous voice.
I woke up this morning still thinking about it and saw this in the Times: http://www.nytimes.com/2013/04/04/science/space/new-clues-to-the-mystery-of-dark-matter.html?pagewanted=all&_r=0
I kinda wish I'd had that article the night before.
Just finished listening to this little thing on the NPR website.
http://www.npr.org/2013/03/29/175741693/segment-2
This one was from last week's "Science Fridays". It was a segment about collisions and their effects on our solar system.
The most interesting part was about the creation of the moon. I'd heard before that the moon might have been formed from part of the earth but I never really understood what that meant. In particular I always imagined that some solid object, like a comet or astroid, had hit the already solid earth and sent off a chunk which became the moon.
It turns out that this was a total misunderstanding. For one thing, if the collision took place, it happened while the earth was still somewhat molten. And it wasn't a collision with a small thing, it was a collision with another planet sized thing, which was also not solid.
Even more interesting it turns out that this model isn't really supported by some current evidence. Most of what the moon is made up of is the same stuff the earth is made up of. If it was formed by a collision of the earth and another planet then the moon should be made up of some of that other planet's material.
Despite this evidence, the scientists being interviewed said he'd "bet his career that some kind of a giant impact that formed the moon". He's just not sure what kind.
This appears to be a much smaller type than the type they use as standard candles. They do however come from binary stars just like the other ones (these ones come from binary stars with white dwarfs). Astronomers also think these ones come from much younger stars since none are found in elliptical galaxies which have less young stars.
It's interesting for me reading these articles since I now know what terms like "elliptical galaxies" and "standard candle" mean. I feel like I've always read scientific articles in mainstream press but I must of just unconsciously skipped over these words. I wonder how many words I skip over without even knowing it.
