Mysteries of the universe

Finally finishing up the series from Astronomy Cast on mysteries (...of the solar system, of the galaxy.) This one on the universe, naturally.

The show notes are located here and here. As usual, any additional links came from these sources.

1.) It all started with a Big Bang-Hey!: but-why? The universe, as Edwin Hubble knew, is moving away from itself and this expansion originated from a single point. The Big Bang Theory perfectly explains the universe that we observe today but it doesn't explain how it got here. This has been complicated by the results of WMAP (Wilkinson Microwave Anisotropy Probe) which studied the after-image of the Big Bang, the Cosmic Microwave Background which showed that the universe was too homogeneous. There are different theories for the cause: a quantum bounce, something about cosmic foam and the multiverse. But because the Big Bang occurred before time, we don't know and don't know (for now) how to know.

2.) Inflation: on a related note, what exactly "banged" and started the expansion? This deals with a very specific and minute period of time in the first second following the Bang event-well, maybe after the Bang event or, maybe before-when objects when matter was moving away from each other at faster than light speeds. Now, this is confusing and seems to contradict Einstein so Pamela qualifies this by saying, "Now, it wasn’t that they were moving through space faster than the speed of light. It was that the whole universe was expanding such that two points seemed to be moving apart faster than the speed of light, which is completely legal according to relativity." Inflationary theory says the cause is a form of repulsive gravity. Again, the reason this theory of inflation is so appealing is the homogeneous appearance of the universe. There are some good graphics on this here and more than you'll ever want to know here.

We don't know what triggered this high-energy even or what stopped it, partially because it's hidden behind the CMB. Which brings us to...

3.) Will we ever be able to see past the Cosmic Microwave Background: Here's (one of) the important things to remember about the CMB--it's not the glowing remnants of the Bang. It's 300-400 thousand years afterwards when the universe had cooled enough that it was no longer opaque (the opacity was caused by the constant absorption and re-absorption of photons.) One way we might be able to peer past it in the future is with gravitational wave detectors instead of using the spectrum of light. In fact, it might be the only way. But we have to get much better at detecting gravitational waves. The big advantage of gravitational waves is that, while they weaken by distance traveled, they are unchanged by anything they come in contact with, unlike electromagnetic radiation.

4.) What the hell is dark energy: Oh, this thing again. Our understanding of dark energy dates back to 1998 when two competing scientific teams were trying to measure the rate at which the universe's expansion was slowing down (which was as we understood it at the time, because of the gravitational drag caused by all the large masses out there) by studying supernovae. Instead, they found it was expanding. They thought they had made an error and squandered their Hubble time. Much math ensued. But, no. It's not slowing down, it's expanding faster and faster.

5.) Do galaxies top off or bottom out: Amazingly, we don't really understand galaxy formation, which began forming around 13 billion years ago. There are two theories.

"Top-down" says you have a large swirling cloud of gas and dust. The cloud begins collapsing due to internal gravity (so, the galaxy that is formed is smaller than the original cloud.) The speed of the original rotating cloud determines whether you get an elliptical galaxy (slow rotation) or spiral (fast rotation.)

"Bottom-up" galaxies are formed by the attraction of a number of small clumps. As the clumps, uh, clump together it draws more clumps. If this theory is correct, then the universe would exhibit more small galaxies than larger ones and superclusters would still be in the process of forming. Both of these things are true.


The upcoming-and delayed-James Webb Telescope could provide the answer here.

6.) What came first-the galaxy or the supermassive black hole at the center: this question becomes more intriguing when you consider the mass of the black hole seems to have some correlation with the mass of the galaxy that surrounds it.

More specifically, it relates to the mass of the bulge. The bulge refers to a tightly packed group of stars when viewing a galaxy. It gets a little esoteric with elliptical galaxies (or maybe I'm just tired) as they say the whole structure is the bulge but you can easily see it here in this image of the spiral galaxy Messier:

The bulge can be said to begin where the spiral structure appears to end.

The supermassive hole equates consistently to around 1/1000 the mass of the bulge. So, did one precede the other or did they form in concert somehow? This is another question that they hope the James Webb will answer as we'll be able to look further away at more galaxies and see if the presence of the black hole and the ratio holds constant.


7.) Whither the green galaxies

8.) Dark matter: you can't have dark energy without bringing up dark matter.  The good news is that while we are a ways away from figuring out dark energy, we are evidently close to a breakthrough hopefully on dark matter. The notion of dark matter, like dark energy, again comes from an observation of something moving too fast. In this case, it's the rotation of galaxies that are rotating faster than their observable mass should allow.

When it's existence was first hypothesized, one of the competing theories was that gravity acts unpredictably over long distances. At least they've been able to can that theory. Unpredictable fundamental forces stress me out. And whatever dark matter is, it appears to be non-baryonic in nature; that is, not made up of things made up of quarks-protons and neutrons essentially. And needless to say, it doesn't interact with the electromagnetic spectrum hence its name. Apparently using neutrino detectors, they are getting some nibbles.

Related question, where then are the dark matter galaxies?

Mysteries of the galaxy

Continuing with the Astronomy Cast theme, here is their list of the top 10 mysteries of the Way, Milky.

The show notes are located here and here.

1.) Blue stragglers: are stars that appear to stay in their youth longer than expected, even regressing to their hotter youths. They're big and blue and given where they are located (in globular clusters), they should have burned more hydrogen than they seem to have. It seems they might be stealing mass from other stars although that's just speculation.

2.) Some of our supernovae are missing: The math says we should see 2-3 a century. The last one that occurred relatively close to us was in 1680.Chandra appears to have found remnants of supernova explosions in some dust clouds. What astronomers can say is there doesn't seem to be anything unique to our galaxy to explain why they can't see them. It may just be a question of not seeing them in the visible spectrum due to obstruction.

3.) The Small and Large Magellanic Clouds: these are the satellite galaxies that are...orbiting the Milky Way? Apparently, we don't quite know. They might be just be dwarf galaxies nonchalantly traveling past us. The explanation for why we can't tell is, once again, mathy but it has to do with factors like our inability to precisely estimate the Milky Way's mass. If they are orbiting us, it's possible the Milky Way will rip them up one day and gobble their stars. Andromeda is going to do the same thing to us, but it's billions of years away so I'll focus on worrying about Michelle Bachman actually winning the Republican nomination for now.

4.) Proxima Centauri's intimacy issues: Proxima is a red dwarf in the Alpha Centauri system, around 4 light years away. The problem is, it's awfully close to Alpha Centauri A&B. Some say it's a captured object that is orbiting this system. They all appear to be moving through the sky close together at around the same velocity.

5.) When is Eta Carinae going to blow already: this is one of the brightest stars in the sky, around 100 times the mass of the sun. It's located in the Homunculus Nebula (it's a great name, it just means "little man.") Stars in constellations are named according to their brightness. Thus, Alpha Centauri is the brightest star in Centauri, this Beta and so forth. Eta took the giant leap forward in 1843 when it brightened and appeared to be supernova-ing. There's no way to predict when. If you happen to be watching with the right kind of equipment, you can see the xray burst minutes before the eruption.

6.) One of our spiral arms is missing-or not: apparently when you study galaxy arms (and of course, such a specialized field exists), you are supposed to look at them all in the same color. But when you look at galaxies through different lights (radio, ultraviolet) the morphology changes. And parts of the arms could be obscured from us. I admit, I don't totally see the big deal about this one since part of it seems to apply to all galaxies.

7.) Where are the Sun's nebula buddies: Around 4.6 billion years, our solar system formed out of a solar nebula. When we look at other stellar nebulae (e.g. Orion, Carinae, Pleiades), we see clusters of stars. It could be due to gravitational effects that the rest were flung out of the system. You can't tell from looking at a star or its motions where it started out so to find out if another star was birthed with our sun, you'll need detailed chemical analysis. I gather this is a somewhat moot point because the answer, by present means anyways, it never much more than maybe and siblings could be on the other side of the Galaxy just as easily by now.

8.) The 60 million year extinction cycle: Here's some cheery reading--10 potential causes of mass extinctions from gamma rays to magnetic field reversals. UC Berkeley contends that around every 60 million or so years, some mass extinction event occurs that wipes out up to 90% of life on this planet. How old is that KT Boundary again? Yup, we're about due. There are some interesting theories about what is protecting us, at least most of the time including the Milky Way's proposed magnetic field.

9.) The case of the missing G-Dwarfs: G-dwarf are also called yellow dwarfs although that can be misleading (they range in color from white to yellow.) They are a subset of the main sequence stars, like all dwarfs. Our own sun is a G-dwarf, but the ones we are looking for would be a little smaller than the sun. Here's how the reasoning goes: the smaller the star, the longer it burns so the longer it hangs around burning through its hydrogen. There are a (at this point theoretical) group of stars formed just after the Big Bang called Population III. They should have little to no metal in them, as they should have formed before being polluted by supernovae. There should also be red dwarfs composed of this primordial hydrogen. It's possible the big stars (that form faster) just didn't leave room or resources for the smaller stars to develop. Or maybe the lack of metals in the primordiverse just prevented smaller stars from forming.

10.) The intermediate black hole quandary: an intermediate black hole would be greater than a stellar black hole but obviously not a supermassive black hole. The moniker "supermassive" always seems to me to indicate its kind of rare but in fact, the intermediate ones are the hard ones to find. They've tried looking in dwarf galaxies and globular clusters but no dice. Chandra has identified some extra-luminous x-ray sources  that might turn out to be the culprits.

Mysteries of the solar system

Astronomy Cast did a two part series each about mysteries of the solar system, the galaxy and the universe about a year and a half ago and I'm just now . It was way too much to absorb in a podcast so I'm going to try to recount all of them here. All information originated from their site or links provided by them.

First, the solar system.

1.) The Pioneer Anomaly: the Pioneer spacecraft (10 and 11) are heading towards the edges of our solar system but not at the speed they are expected to travel, they seem to be slowing down. The data has been difficult to analyze because some of the tapes have been misplaced and the the data was never intended to be analyzed this way. And the explanation is really....mathy. But it points to a possible significant misunderstanding on our part of the laws of physics. The Planetary Society is in the process of doing the largest analysis ever of 30 years worth of data.

2.) Axial tilts of Uranus and Venus: the Earth is tilted at 23.5 degrees. Uranus is tilted at 98 degrees when compared with the orbital plane of the sun (people sometimes ask tilted in comparison to what? There's your answer.) Whereas other planets can be thought of as tops spinning around the sun, Universe Today says Uranus is more like a rolling ball. The common wisdom these days is something big smacked into Uranus to flip it over on its side where it couldn't get up, like my dog sometimes.

For Venus, the tilt is a whopping 177.3 degrees. This means it's essentially upside down. This is why it rotates backwards (or clockwise when seen from above) as compared to all other planets in the solar system. The upshot of the almost upside down tilt is that the net difference versus the plane of the ecliptic is only 2.7 degrees so no seasons. Why is Venus jacked up? It could be caused by some asteroidal bombardments in the days of the early solar system. Key word to understand: Kirkwood Gaps.

3.) What's beneath Europa's ice? Io takes more pounding from Jupiter's immense gravity. Europa, which is one of the brightest objects in the solar system due to reflection, might have a warm, salty ocean under its icy crust if the probe data is correct. The hope is there's life under there.BTW, here's an acronym for remembering the names and positions of the Galilean moons in order from furthest in: I Eat Green Cows.

4.) Methane on Mars: the question is where is it coming from and how is it getting replenished. Due to the conditions on Mars, Methane only lasts a few hundred years. Is it geological activity or is it, again, life? If it's geological activity, it means Mars is not, as we've thought, geologically dead. Or maybe it's coming from meteorites.

5.) Titan's atmosphere: another question of, for one, where is the Methane that makes up less than 2% of the atmosphere coming from. It seems to be coming from a phenomenon known as cryovolcanism. It's also fascinating because it's a little moon with an atmosphere about 1.5 times the size of our own.

6.) Corona temperature: the corona is where the solar winds originate. It refers to the area around one million kilometers from the surface. Temperatures reach one million degrees. But the surface is only 5000 degrees. Why is the corona so hot and what is making it so hot? The preliminary answer involves magnetic field lines.

7.) The Kuiper Cliff: the Kuiper Belt starts sooner than I realized, within the orbit of Neptune. The prediction basically is that the further out you go, the more objects you should find. Instead, there is a sharp drop-off around 50 au's. What this means, according to a dude named Patryk Lykawka, is that there could be another planet out there sweeping its orbital path clean.

8.) Why are there long period comets: these are comets that have periods ranging from 200 to 10 million years. This means their orbits are very long ellipses. This could mean there's a planet in the area of the Oort Cloud that is periodically knocking objects loose into these crazy orbits. This does not mean that Planet X will return from the fifth dimension to destroy the world in 2012 like the Mayans thought. Another cool tidbit: the Oort Cloud isn't definitely proven but we can see what looks like it's "shadow" in the CMB. Cool.

9.) The geysers of Enceladus: Cassini has confirmed there are geysers ejected regularly from the South Pole region of Enceladus, one of Saturn's moons. And the geysers are of water and ice which means that maybe there's a warm ocean underneath somewhere. These geysers appear to be replenishing Saturn's rings. And Enceladus appears to just be an icy moon, like so many others. Why is it the only one (we know of) doing this weird thing?

10.) The Saturn Hexagon: another Cassini discovery, or rather confirmation since it was first seen by Voyager. There appears to be a perfectly shaped hexagonal hurricane on Saturn's north pole turning at the same speed the planet is rotating. A giant planetary hurricane is cool but not unheard of. But physics says it should be a circle. And by giant, I mean really giant. The sides are 14,000 kilometers.

The video is said to be quite amazing but...well it's all relative isn't it? It's amazing we can even get video from Cassini. Anyways, here it is.

A gaggle of NASA stories

There's been a lot of interesting NASA stories of late.

One, poor Spirit finally gave up the ghost. The rover was put into hibernation last March but alas, it doesn't seem to want to wake up. The little card table sized explorer sure gave NASA more than its money's worth though.

With the shuttle retirement in progress, NPR did a great story about the Crawler, the giant vehicle used to tow the shuttle to the launch site. It's one of those things most people never think about but it's a huge bit of engineering. It's top speed is 2 miles an hour. Only 6 people are authorized to drive it. The drive down the 3.5 mile specially built service road takes hours as even the top speed can't be approached with the multi-ton shuttle and its rockets in tow.

Finally, the James Webb telescope is going to be the successor to Hubble. Unlike the Hubble, it is not intended to be serviced by the Shuttle so it's going to be out in L2. It's pretty cool, it has to fold up to fit inside of a rocket. They referred to it as the "origami telescope." Alas, it's overbudget and now apparently will take years longer to complete. Currently, they launch date has been pushed to 2018.

Epistemophilia: quasars and the Catholic Church--both destructive in their own way

So, I was listening to an Astronomy Cast recently about quasars. Here's the thing--I never really understood them. Typically people say something like, "Well, no one does." And this is on the happy occasion that I'm talking to someone who knows what a quasar is, vaguely.

Yes, I know it stands for "quasi-stellar object" or, originally, "quasi-stellar radio srouce" because it was first discovered by radio telescopes in the 1950's and the energy looked like a star but it was red-shifting like a galaxy. The degree of red shift indicated it was moving away from us very fast. Now they are considered high energy galactic nuclei. Wikipedia says that a galaxy hosting an AGN (active galactic nucleus) gets its radiation from the supermassive black hole at its center (I also learned that astronomers originally referred to these as "angry monsters." I like it.)

Wait, does this mean the Milky Way is an active galaxy? We have a supermassive black hole too. NASA says no. An active galaxy is any that emits enormous amounts of energy (xrays, gamma radiation, etc.) caused by an object at its center. I guess we don't emit enough. I expect that's a good thing, to understate.

So, quasars and black holes aren't the same thing, y/y? Correct. The current thinking is a quasar has a spinning black hole at its center. This site explains it well. The intense luminosity comes from gases in the accretion disc. All of the energy in a galaxy added up would equal one of the brighter quasars. They say a large star would have had to collapse to create its black hole.

Ok, on to something completely different. Nicaea. I heard it mentioned recently in a story about the Crusades and I realized I didn't know wtf it actually is. Greece? Turkey? Syria?  It's Turkey, Western Turkey. The town is now called Iznik. It was the capital of the eponymous Empire. One of the Byzantine emperors hid there during the Fourth Crusade-the one where Rome illogically decided to attack Constantinople in 1204. The Catholics then formed the Latin Empire which lasted until 1261. The Byzantines returned to power Michael VIII but Byazntine fell to the Turks under the rule of Constantine XI.

All good preparation for when  I eventually get around to reading Lost to the West.

In A Corpse in the Koryo, Inspector O meets a Finnish/Chinese prostitute named Lena who is also an intelligence operative living in North Korea. The obvious question as to why the hell anyone would live in North Korea on purpose is never addressed. But she mentions growing up on the shores of Lake Keitele in Finland. It's a lake in what Wikipedia says is central Finland (it looks like southern Finland to me.) Alas, I couldn't find anything really interesting about it but it's pretty. Here is a painting of it by a (surprise!) Finnish painter from 1905. The blue of the Scandinavian Cross in the Finnish flag is said to represent the many lakes of Finland.

Epistemophilia: the Great Red anti-cyclone

So I was watching something about Jupiter in the gym the other day and they mentioned that the Great Red Spot is an anti-cyclone, not a cyclone. Because it turns in the direction opposite that the planet rotates. That's kind of fascinating, no? It can happen on this planet too but the fluid dynamics get all crazy complicated. For a storm on the Earth to be anti-cyclonic, it would have to rotate clockwise in the Northern Hemisphere and counter-clockwise in the Southern Hemisphere.

The Great Red Spot rotates counter-clockwise. Here is what I don't understand: as seen from above, most planets in our solar system, including Jupiter, appear to rotate counter-clockwise. The exceptions are Venus and Uranus (although some sites list only Venus and some others list Pluto as well.) So wouldn't the Great Red Spot be a cyclone if it's moving in the same direction as Jupiter? Must keep looking for the answer on this.

(there is also a smaller storm called the Little Red Spot which was until recently white. They think the storm kicked up materials that had a reaction to ultraviolet light and changed color in a chemical reaction.)

There is a similar storm on Neptune called the Great Dark Spot and on Saturn called Anne's Spot. Apparently there are also anticyclones on Venus' pole.