# I saw the Stars in my cereal this morning [SPACE](NSF ALIENS and 56K)

## Posts

• FAB FRESH RAIIINBOOWWWWWRegistered User regular
Instability of the atmosphere is equal to the rate of change between the beginning of Z and indefinite end of Z where the original rate is Tornado velocity 1 minus the tornado velocity inside the environment divided by the tornado's environmental velocity?

Is it a formula to determine the state of the atmosphere surrounding a tornado based on the velocity of the tornado itself and how it's velocity has changed since Z?

If that's true I would say it is used to project the most likely path of the tornado!

• All the Wizards Under A Rock: AfganistanRegistered User regular
Science related!

New Volcano in the middle of the ocean!

A new volcano that was hiding out under the water near Japan decided to peak up and say hi! There seems to be a lot of volcanos going off in the southeast pacific lately, although probably not more than average.

• Monster girl with a snek tail and five eyes Bad puns, that's how eye roll. Registered User regular
HellaJeff wrote: »
Instability of the atmosphere is equal to the rate of change between the beginning of Z and indefinite end of Z where the original rate is Tornado velocity 1 minus the tornado velocity inside the environment divided by the tornado's environmental velocity?

Is it a formula to determine the state of the atmosphere surrounding a tornado based on the velocity of the tornado itself and how it's velocity has changed since Z?

If that's true I would say it is used to project the most likely path of the tornado!

Not quite, but good try! CAPE, or convective available potential energy, is a measure of just how unstable the atmosphere in a given spot is in regards to the potential development of convection. It is measured in j/kg. The more CAPE the greater the chance you will have for storms to form. Tv in the equation stands for virtual temperature and Zf is the height of the level of which free convection can take place and Zn is the height of which neutral buoyancy of a parcel of air rising begins.

Instead of using this equation ourselves, us meteorologists are lazy and send up sounding balloons (aka weather balloons) to fill in the values and then use a computer to draw out a nice Skew-T plot for us to help one visualize the depth and abundance of the values of CAPE and CIN (convective inhibition, the opposite of CAPE) throughout the levels of the atmosphere. They look like this:

These skew-t plots also tell us things like quality of depth of moisture, where the base and anvil of a storm will form, and at what level hail will begin to form.

• Registered User regular
I have a question Chimera!

Whenever a big storm comes through my area of northwest ohio and has the potential for rotation or tornados the local news always points out that the more likely areas tend to be in jaggy areas in the leading edge of the storm and particularly at either the top or bottom of the large bow shaped storms that pass over us.

Also tornados seem to hit to the south of us far more frequently than actually in the lucas county or toledo areas and I was wonder if there is like a real sciency reason they seem to be less frequent here, I mean we are right on top of the bottom shore of lake erie.

• Monster girl with a snek tail and five eyes Bad puns, that's how eye roll. Registered User regular
Absolute luck is what has caused the storms to affect the area south of you more. There isn't much in the way of orographic features to prevent storms from making it into your county.

The meteorologist on your television was probably trying to explain where on the radar image of the storm the tornado could be found so let me give you some examples of what he was trying to convey. Keep in mind that in each image north is the top, south is the bottom, east is the right, and west is the left side of the image. In each image we will assume we are in the northern hemisphere and that storm motion is from left to right across the image.

Example 1, the classic discret supercell:

Here we have a classic supercell all by itself. This is what most chasers seek in the field due to the unobstructed view of the updraft that this storm will commonly have. This is the kind of storm that has what your tv meteorologist will call a "hook echo" and it is in this echo that your tornado will exist. The hook echo is caused by the dust, debris, and precipitation that is in the storm's rear flank downdraft, or RFD. This is what wraps around the inflow of the storm's updraft and tightens up the circulation under a storm to form a tornado. If your tornado is strong enough it will form a large ball shape at the end of the hook echo. This is known as a debris ball and is an indication of massive damage being generated as the radar site is seeing pieces of structures and landscape being lofted into the path of the radar beam by the tornado.

Example 2, the LEWP or line echo wave pattern:

The LEWP is a brief mesocyclone (rotating updraft of a storm) that forms in a QLCS (quasi-linear convective system) which is also known as a squall line to the layman. It forms when a brief kink in the squall line allows for an area of low pressure to form. It is often the result of a segment of the line bowing out. This will occur when the cold pool, or a downburst behind the main line pushes out a segment of it, causing it to surge forward from the rest of the line in the shape of a bow. This will only be further exacerbated by the mesocyclone as it forms an RFD that will push around its backside into the bow and cause it to tighten up its own rotation until it chokes itself off.

Although extremely uncommon these can produce violent tornadoes that are semi-long track. Most commonly though the tornadoes produced by this happen for only a few minutes at best and are not strong. They can even happen between the 3-5min intervals of the radar scan and be missed entirely by radar. They often take on an S shape on radar as opposed to the classic backwards J shape of a hook echo. They will spawn a tornado along the leading edge of the QLCS or just inside it and these tornadoes are almost exclusively wrapped by rain. A serial derecho can spawn a tornado outbreak by having many LEWPs along its line.

Example 3, the bookend vortex, or the comma head:

The last example I will give you here is the bookend vortex, or BEV. This feature will commonly be referred to on TV as the head of a comma due to its appearance on radar. It forms as part of a QLCS only instead of being with in the line segment or between multiple bows it caps off the top of one. It can also be found in a HP (high precipitation) supercell that is transiting to an outflow dominant structure as it's mesocyclone becomes occluded. When this happens the mesocyclone will die and the supercell may not be able to recycle and become either a bowing segment or dissipate.

The BEV is formed in a QLCS when a portion towards the top, or when the entire system begins to bow out as it surges forward. As is shown in the first image below when this happens you will get rotation that forms along the tip of the line at the top and bottom. The rotation along the southern end of the line will be anticyclonic (clockwise) and not be able to form a mesocyclone due to this fact. On the northern tip the rotation will become cyclonic (counterclockwise) and will often lead to the formation of a mesocyclone or a small family of them if the circulation is tight enough.

The tornadoes that can spawn from these will vary in strength and length on the ground. The life of the mesocyclones will be fragile as if the storm bows out too fast it will occlude and choke off the meso and tornado. Too slow and the vorticity at the north end of the system will not be enough to create a mesocyclone or sustain its rotation. In the right circumstances these systems can produce strong tornadoes with longer tracks but more often than not they will produce brief tornadoes of the weaker variety like their LEWP cousins. Unlike the LEWP tornadoes, the BEV tornadoes do typically have more warning since they take longer to organize and can be seen more easily on radar.

A BEV or comma head will always form behind the line. not ahead of it. It will look like a big curl, ball, or spiral on the north end of the line. In a progressive derecho you will find the BEV to often produce tornadoes and can at times become something larger and more sinister which, a mesolow, mesoscale convective vortex (MCS), or wake low. Those are subjects for another day though and the tornadoes that occur in them behave and look similar to ones found in a normal BEV.

(Tornado will be under the letter C in the image above.)

I hope that clears that up for you. Let me know if this helps or if you or anyone else has any other questions!

• Registered User regular
That's a pretty alright storm. It's got a great hook though.

bnet: TheStig#1787 Steam: TheStig
• Registered User regular
edited November 2013
Xehalus on
• AtlantaRegistered User regular
edited November 2013
To relate the BEV-style to something more common, you can fill up a tub of water and move your hand through it. You'll see some swirly bits around the edges, and this is the same kind of thing that can happen around the edges of a line of storms. In a storm, the part of your hand is played by the advancing edge of a pocket of cool air that has descended from higher up in the atmosphere.

The major conceptual leap (from a science perspective, anyway) that you have to take in meteorology (and aerospace engineering) is that the atmosphere is basically a fluid and behaves more like a liquid structure than a pure gas.

a5ehren on
• Monster girl with a snek tail and five eyes Bad puns, that's how eye roll. Registered User regular
a5ehren wrote: »
To relate the BEV-style to something more common, you can fill up a tub of water and move your hand through it. You'll see some swirly bits around the edges, and this is the same kind of thing that can happen around the edges of a line of storms. In a storm, the part of your hand is played by the advancing edge of a pocket of cool air that has descended from higher up in the atmosphere.

The major conceptual leap (from a science perspective, anyway) that you have to take in meteorology (and aerospace engineering) is that the atmosphere is basically a fluid and behaves more like a liquid structure than a pure gas.

Yay! You have become my new best forum friend! Sorry @Melding, you've been replaced. Fluid dynamics is a major part of meteorology. Concepts like convection and advection play put in out atmosphere in much the same way it does in a pot of water or your bathtub. One way I like to explain a BEV, or the RFD's creation of a tornado is to tell people to picture the blade of a canoe paddle passing through the water. The bald acts as the RFD or the cold air pushing out and the eddies that form on the edges would be your areas of rotation. It is exactly the same as your analogy. You're my hero!

• AtlantaRegistered User regular
Ha. I remember just enough of my thermodynamics classes to be dangerous. I'm a EE by trade, but I'm an interested amateur when it comes to weather stuff.

• Monster girl with a snek tail and five eyes Bad puns, that's how eye roll. Registered User regular
a5ehren wrote: »
Ha. I remember just enough of my thermodynamics classes to be dangerous. I'm a EE by trade, but I'm an interested amateur when it comes to weather stuff.

An EE? Teach me how to build robot armies!

• Registered User regular
How accurate is the movie twister with regards to throwing your recycling into the funnel to study it's interior?

...

I had a crush on helen hunt in that movie.

• AtlantaRegistered User regular
Chimera wrote: »
a5ehren wrote: »
Ha. I remember just enough of my thermodynamics classes to be dangerous. I'm a EE by trade, but I'm an interested amateur when it comes to weather stuff.

An EE? Teach me how to build robot armies!

Robotics is hard :P, I do computer stuff and semiconductors.

I did take a weather radar class from the Atmospheric Science department for the hell of it when I was working on my Master's. It was fun to watch all of their students take a 2 week crash course in electromagnetic properties

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• Registered User regular
Chimera wrote: »
Sorry Melding, you've been replaced.

Fucking Finally.

• Monster girl with a snek tail and five eyes Bad puns, that's how eye roll. Registered User regular
Melding wrote: »
Chimera wrote: »
Sorry Melding, you've been replaced.

Fucking Finally.

I was a bit to hastey, he can't build me that robot army after all so you move back to the top. :c

• Monster girl with a snek tail and five eyes Bad puns, that's how eye roll. Registered User regular
Uriel wrote: »
How accurate is the movie twister with regards to throwing your recycling into the funnel to study it's interior?

...

I had a crush on helen hunt in that movie.

Twister is a comedy to me. There were some VERY minor and loose truths in the film in regards to how Jonus is an asshole and some big sponsored chasers were like him in real life but even that really isn't the case anymore and wasn't at the time the film was made. Beyond that the movie is pure fiction in how storms behave and sending coke cans into storms will not produce science. The current method is to use mobile radar trucks to look at the storm from 500ft above the ground and up. To close the gap from the ground to 500 ft above ground Tim Samaras would deploy probes that stayed on the ground. They looked like flattened orange traffic cones.

Until Tim came along no one had been successful with probes and with his passing there is no one currently deploying probes. NOAA tried to with a probe they called TOTO. Pictured below along side the movie props you can see that it was the inspiration for Dorthy from the movie. TOTO is the orange colored probe. It differs from Dorthy in that it does not open up and release probes. The drum mostly added weight to hold it to the ground. The probe was illy designed and was too hard to deploy safely. If one did deploy it the probe would have easily been tossed and the data would not have been very useful.

One thing interesting about Twister is that all the terms they use are real terms in chasing and meteorology. Storm chaser Warren Faidley helped them with the vocabulary they use in the movie but sadly they did not review the definitions they gave him and not once are any of the terms used properly. This only adds to the comedic value for my self and leads to many inside jokes among chasers when we facetiously quote the movie while chasing.

• Registered User regular
I love the idea of actual storm chasers quoting Twister ironically and giggling.

• Monster girl with a snek tail and five eyes Bad puns, that's how eye roll. Registered User regular
We do this all the time. We also are a big fan of Sharknado and other such stupid weather flicks!

• Registered User regular
Anyone know what's up with ISON? I hear it's dead, or at least dead enough.

• Put your goddamned hand in the goddamned Box of Pain. Registered User regular
edited November 2013
Well, they had trouble at perihelion and they thought it might have disintegrated for a couple hours, but since last night something has poped up, but they're not sure exactly what or how much is going on. But there's signs that some of the nucleus has remained intact.

http://www.nasa.gov/content/goddard/comet-ison-may-have-survived/

Fishman on
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That's unbelievably cool. Your new name is cool guy. Let's have sex.
• Registered User regular
That's good.

• Monster girl with a snek tail and five eyes Bad puns, that's how eye roll. Registered User regular
She emerged as a headless comet, or at least that is what I assume has happened as this morning's SOHO image paints a pretty bleak picture. You can see ison near the top of the image.... or at least a ghost of its tail.

• Registered User regular
Maybe the head of the comet went back in time and the aliens riding it are going to transport some whales to the future.

• Monster girl with a snek tail and five eyes Bad puns, that's how eye roll. Registered User regular
Updated video showing ISON as she dies. Watch and weep over the loss of our comet friend which we all had such high hopes for.

http://science.nasa.gov/media/medialibrary/2013/11/30/ghost_anim.gif

• I'm a wizard And that looks fucked upRegistered User regular
Yeah I was really hoping ISON was gonna be this crazy cool thing we all got to see during the day and it was gonna be all once in a lifetime.

http://atlanticus.tumblr.com/ PSN: Atlanticus 3DS: 1590-4692-3954 Steam: Artreus
• thats what my hearts become in that place you dare not look staring back at youRegistered User regular
so do you think that comet seeded life onto the sun?

• Monster girl with a snek tail and five eyes Bad puns, that's how eye roll. Registered User regular
Foolproof wrote: »
so do you think that comet seeded life onto the sun?

As a scientist I can soundly confirm this suspicion with a solid yes.

• FAB FRESH RAIIINBOOWWWWWRegistered User regular
Chimera wrote: »
HellaJeff wrote: »
Instability of the atmosphere is equal to the rate of change between the beginning of Z and indefinite end of Z where the original rate is Tornado velocity 1 minus the tornado velocity inside the environment divided by the tornado's environmental velocity?

Is it a formula to determine the state of the atmosphere surrounding a tornado based on the velocity of the tornado itself and how it's velocity has changed since Z?

If that's true I would say it is used to project the most likely path of the tornado!

Not quite, but good try! CAPE, or convective available potential energy, is a measure of just how unstable the atmosphere in a given spot is in regards to the potential development of convection. It is measured in j/kg. The more CAPE the greater the chance you will have for storms to form. Tv in the equation stands for virtual temperature and Zf is the height of the level of which free convection can take place and Zn is the height of which neutral buoyancy of a parcel of air rising begins.

Instead of using this equation ourselves, us meteorologists are lazy and send up sounding balloons (aka weather balloons) to fill in the values and then use a computer to draw out a nice Skew-T plot for us to help one visualize the depth and abundance of the values of CAPE and CIN (convective inhibition, the opposite of CAPE) throughout the levels of the atmosphere. They look like this:

These skew-t plots also tell us things like quality of depth of moisture, where the base and anvil of a storm will form, and at what level hail will begin to form.

Awesome! It was fun to try and figure it out without looking up any hints

• Registered User regular
I've got one word for you, and that word is "PSR J1748-2446ad". Ok that's not a word. Shut up.

Notable features:
• Is a pulsar - so it's a spinning ball of pure neutrons jetting fucktons of radiation out of its north and south poles.
• Being a neutron star, it's more spherical than any other object in the universe, manmade or otherwise.
• It's only 20 miles across, but the entire thing is packed more tightly than an atomic nucleus.
• It spins on its axis 716 times per second. That's a full revolution every 1.396 milliseconds.
• If you take its diameter and speed into consideration, the land speed at it's equator is 24% the speed of light! Fuck!

• Put your goddamned hand in the goddamned Box of Pain. Registered User regular
Oh, damn it. Late last week another Nova erupted in fucking prime viewing location from my back yard - the brightest Nova this century - and I've been so busy over the weekend I didn't check my newsfeeds about it until now.

I feel like a damn idiot.

Oh well, seeing as I don't really have a car at the moment anyway it's not as if I could get to any of the really good dark sky locations. But I might head down to the south coast tonight and see what's visible. Looks like it should still be magnitude 4.5 or so.

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That's unbelievably cool. Your new name is cool guy. Let's have sex.
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So it looks like there's water vapour erupting from the surface of Europa. Now correct me if I'm wrong, but we currently don't have any proof that there's currently liquid water there? Now the article explicitly states that this doesn't prove that this is the case, but it's certainly a tantalising hint!

Imagine the view if we ever manage to colonise the place! Little bit on the nippy side though... Also not much atmosphere... Or sunlight...

Think I'm gonna go turn up the office heating a little, I'm starting to feel a chill!

• Registered User regular
All of these worlds are ours except Europa

• Put your goddamned hand in the goddamned Box of Pain. Registered User regular
I think I just got some mad photos of this Nova after waiting all week for the skies to clear.

But it's 3am and I have to pick up a friend from the airport tomorrow so I won't be able to edit them for a couple days.

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That's unbelievably cool. Your new name is cool guy. Let's have sex.
• RAGE vympyvvhyc vyctyvyRegistered User regular
Fishman wrote: »
I think I just got some mad photos of this Nova after waiting all week for the skies to clear.

But it's 3am and I have to pick up a friend from the airport tomorrow so I won't be able to edit them for a couple days.

Why tease us like this? Whyyyyyyyyyyyyyyyyyyyyy

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hi guys it's snowing really bad here.

@Chimera what can you tell us about snow storms?

• Put your goddamned hand in the goddamned Box of Pain. Registered User regular
So as noted above, a Nova Centauri 2013 flared up a week and a half ago to become (at present) the brightest Nova since 1999 and is not far off being one of the 10 brightest novas on record, which is kinda cool.

Unfortunately, I've not had much in the way of clear skies here, despite my excellent viewing latitude - Summer appears to have abandoned us and it's been a bit muggy and overcast for about a week, but on Friday a couple things happened that changed matters -
1) In the evening, looking out at the cloud and checking recent weather satellite photos, it appeared that the cloud might be breaking up on the hills
2) I got a loaner car from the dealership we're using to replace the one that got written off in an accident at the start of December, meaning I was mobile enough to get out to some out of the way locations.

Thus enthused by news that the Nova was starting to brighten again after some intial dimming, I threw my photo gear in the car and headed out to Wellington's South Coast.

I'm going to level with you: I thought I was running a fool's errand. When I drove out of my driveway at midnight, the cloud cover was still horizon-to-horizon. I live at the Northern end of what is termed the Northern suburbs, so to reach the South Coast, I have to drive through the city; the moment I took the city offramp, I started to get hit by a light drizzle that required me to flick on my wipers and drive to the coast in a haze. Fortunately, at half past midnight traffic is pretty light so I made good time. And the moment I hit the south bays, I was able to turn off the wipers and start looking for vantage points.

My first stop was Island Bay. The cloud cover was still heavy, but the rain had stopped and the view, though doused in sodium streetlamps, is pretty spectacular. I had a short walk along the shoreline to see if I saw anything I liked, and as I was doing so, I saw the first breaks begin to creep through the cloud cover - little windows into the starry sky. As I was gazing up at the the very first of these, it managed to perfectly frame one of the most spectacular shooting stars I've seen in my life - this weekend was also the peak of the Geminids meteor shower, and it hit me with a huge bright fireball that you could see break up in the upper atmosphere, shedding outer layers like a fuzzy furry tail.

Taking it as something of a good omen, I unpacked my camera and started shooting what I could see.

After about 20 minutes, I managed the above shot, capturing both the pointers, the Nova, and the Southern Cross over the island of Island Bay. The Milky Way stretches up above, and in the distance on the horizon you can make out the distant bright light of the Pencarrow Lighthouse at the harbour entrance. The cloud pattern was breaking up slowly, but it seemed particularly stubborn to the east, so I decided to pack up again and head west to Owhiro Bay to see if I could get clearer skies from further over. This would also have the added bonus of moving to a darker location, as Island Bay is about the brightest point on the South Coast, and you can get much darker skies by travelling a few bays in either direction.

At this point, I was also reminded why I don't often shoot at this time of year - even at 1am, the horizon is still quite bright, and with the moon out until 3-4am, it's really difficult to get true deep blacks that lift out the brilliance of the Milky Way. That said, it was also still a quite comfortable 18-19 degrees, which was a pleasant change from my usual heart-of-winter shooting schedule, and with the Geminids and the Nova I had plenty to look at and shoot.

The above was taken from the foreshore in front of the Bach cafe, one of my favourite places to take out-of-towners essentially for being about the prettiest place to eat in the city. The landscape doesn't quite carry the same under nightscape conditions, but I was able to find a sheltered spot in the lee of a big boulder and sit and enjoy the sky for a while, albiet still with minor cloud cover. Although satisfied, I felt that if I continued to move west, I might have better luck towards the Red Rocks - a place with a distinct lack of any street lighting at all.

Red Rocks is a Seal Reserve and national park, so beyond the car park there is nothing but a long walking track out to the point. I have been meaning to check out the possibility of it as a dark skies shooting location for a couple of years, but had never got around to it until this weekend. On this occasion, I only went as far the carpark, owing to what I presume was a graduation bonfire further down the track sounding distinctly drunken teenager-ish (it is something of a make-out point), but just from wandering around the viewpoints in the carpark I think I'll have to keep it in mind for future.

And here's a helpful guide as to what I've been talking about and what I've been looking at this whole time.

Rather satisfied with the results, I decided to head back to Island Bay to see if the cloud had broken up along the entire coast in the 2 hours I had been out, returning to my original view point (because I liked the outlook across the island), and luckily enough, it had!

I set up my camera in roughly the same spot once more and took the shot I had originally come out to take.

And here again in profile:

All up, I was pretty happy with both the excursion and the results, despite struggling a little with light pollution from streetlamps, moon, and Summer skies.

To close the trip out, I left driving East, out towards Houghton Bay and the darkness of the campground on the point there. Parking up, I left my camera in the car and got out and just stared at the now-cloudless sky for a half hour. I was rewarded with another Geminid meteor: this one a long, bright streak leaving a burning arc across a quarter of the sky. I was unfortunate not to see more or manage to capture any on film, but the few I did see didn't disappoint, being both spectacular and memorable against the bright sky. I thought it an excellent bookend to a thoroughly enjoyable night, got back in my car, and drove home under the setting Moon.

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That's unbelievably cool. Your new name is cool guy. Let's have sex.
• I spend too much time on the Internet Registered User regular
Yup that last picture is now my phone background.

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