FOR SCIENCE!

@Imoyram good point.
i'm glad you see what i'm getting at. it immediately jumped out at me, so, well, i decided to point it out.
looking at the solar system, i can see why you did two browns. the planets aren't really that colourful.
hmmm... maybe you could make the terrestial one red or green, or the gas giant one purple? (not 'cause any of them actually are purple; 'cause to me, purple seems like a good colour for 'not much like earth,' if that makes any sense. and like a bit of a gassy colour).
i hope this helps and that i didn't overstep here.

 

Hmm. Yeah. I could go for colours that just plain dont show up in our planets (purple, bright red, bright green, bright yellow, pink)
What I was trying to do was pick colours applicable to almost all of teh planets in that type of planet if you know what I mean?
Examples
~~~~~Terrestrial~~~~~
Mercury - Grey
Venus - Tan
Earth - fuck earth stu[id doesnt fit blue and green
Mars - red/brown
~~~~~Gas~~~~~
Jupiter - tan
Saturn - Tan
~~~~~Ice~~~~~
Neptune - dark blue
Uranus - Light blue

So I picked for each type
Terrestrial - tan, med. brown, grey
Gas - tan
Ice - blues

Maybe if I threw some flecks of green and blue into the terrestrial one?

 

@Imoyram that makes sense.

flecks of green and blue could do it. if you draw an example of that and post the picture, i could tell you if i think it looks distinctive enough or not.

 

First attempt
Second attempt

It is really busy? But maybe that's okay?

 

@Imoyram i think that'd look different enough, yeah.

 

In tonight's edition of "things that aren't at all like you pictured them" and "vertical exaggeration is not your friend": the Marianas Trench.


Okay, get a good picture of the Marianas Trench in your mind's eye. Got it?

Spoiler: Now open the spoiler.

And there it is. See that gentle "v" shape? Yeah, that's it.
From google earth, with accurate relief, looking more or less straight along the bottom of the "trench". That red point floating up there is the point on the surface of the ocean directly over the Challenger Deep, the deepest measured point in the ocean.
And it is hella deep. Just, the walls of the "trench" aren't very steep at all.

(which makes sense if you think about it. this isn't some erosional feature cutting down into the rock, it's one tectonic plate scrraaaaaaaaping over the top of another.)

Spoiler: and here's a nice view of the very definitely erosional Grand Canyon, for comparison's sake

bit steeper-sided, yah?

 

i was told this terrible thermodynamics/fluid mechanics joke in class & i have to share it

so there's this church. it's a really nice church, it has some nice stained windows or something. the point is everyone wants to go there.
one sunday they're having mass & it is just packed. there's a ton of people going into the church to attend.
so, the joke is: what's the bit circled in red called?


i don't know what a church looks like from the top heh

Spoiler: it's called a punchline because you'll want to punch something after reading this

the mass flow rate

 

There is a gravitational wave press conference scheduled for tomorrow morning! If they've actually seen something at LIGO, it would be SO COOL! I'm going to watch the livestream and I'll update this thread on what they say.

*vibrates with excitement*

 

WithAnH liveblags the LIGO press conference

They've already moved the Goddard Space Flight Center broadcast of the conference to a bigger room twice this week. Standing room only. There is coffee and cake!

Some context before this thing gets started:
One of the major predictions of general relativity is that the acceleration of mass should create waves that stretch and squish spacetime itself. We already had a very good indirect detection of gravitational waves from the Hulse-Taylor binary pulsar, but there had never been a direct detection. The very good reason for that is that unless you're right next to a massive binary system or something, gravitational waves are very weak. By the time it reaches the Earth, the perturbation in distance caused by a gravitational wave from a neutron star binary will be less than one part in 10^20 - possibly much less. To measure such a tiny effect, the LIGO collaboration came up with what might literally be the most precise instrument ever built.

The LIGO (Laser Interferometer Gravitational-Wave Observatory) instrument is a pair of very large earth-based laser interferometers (Hanford, WA and Livingston, Louisiana) that detect the tiny changes in distance caused by the passage of gravitational waves. There's a little video explaining how a laser interferometer works about halfway down this article. It looks simple - and it is a simple principle. The thing that's hard is dealing with all the sources of noise, which in a laser interferometer means anything from seismic noise to air molecules in the laser path to thermal noise in the mirror coatings. LIGO operated from 2002 to 2010 without any detections, and from 2010 to 2015, it received various upgrades and evolved into Advanced LIGO.

Spoiler: Liveblog

10:32: France Córdova, Director of the NSF speaking, giving some history of LIGO
10:33: Showing an inspirational LIGO video with stirring music...
10:34: David Reitze, Laboratory Executive Director at LIGO speaking. "Ladies and gentlemen, we have detected gravitational waves. We did it!" Room erupts in cheers.
10:35: Signal was produced by colliding black holes - matched the theoretical prediction that the frequency of the waves should increase with time.
10:37: Showing a video of a simulation of a binary black hole merger. Individual black hole masses estimated at 30 solar masses. Effect that LIGO is trying to measure is about 1/1000 of the diameter of a proton.
10:42: Reitze thanks NSF, hands over to Gabriela Gonzales, spokesperson for LIGO scientific collaboration.
10:44: Gonzales describing how LIGO works.
10:45: Showing the actual LIGO waveform from the Livingston detector! Peak is one part in 10^21. 7ms later, saw the same signal in the Hanford detector! Signal is exactly what was predicted for black hole coalescence. 3 solar masses of energy emitted in gravitational waves. 1.3 billion light years away. Paper was just published in Phys. Rev. Letters - I will look at the paper later today.
10:49: Played the "sound" of the gravitational wave chirp. Direction: Southern sky, in the direction of the Large Magellanic Cloud. Can't do better than that with only two detectors. When additional observatories come online, they will be able to localize future events better.
10:51: Now speaking: Rainer Weiss, LIGO co-founder. Going into the history of Einstein's field equations. He has a stretchy net that he's using to demonstrate the concept of "strain" in spacetime.
10:56: He's going into how an interferometer works. I'll put some links in the context section. Now talking about how they deal with noise reduction. The mirrors are isolated from the motion of the earth by quadruple suspension.
11:00: Handing over to Kip Thorne, physicist, co-founder of LIGO, and author of Black Holes and Time Warps.
11:02: Kip Thorne now discussing the history of LIGO. Initial interferometers built in the 2000s. Advanced LIGO (with new interferometers) installed between 2010 and 2015. Detection occurred almost immediately, on September 14, 2015.
11:05: Another simulation video. Collision timescale ~200ms, total energy liberated 3 solar masses. Other sources of gravitational waves that may be detectable: neutron stars, black hole-neutron star collisions, supermassive black holes, giant strings(?).
11:09: Handing back to the director of NSF.
11:12: Acknowledging international collaborators. Opening up for questions.
11:15: Question: "This detection actually occurred during instrument checkout, before the instrument was officially turned on. Is this too good to be true?" The scientists don't think so. They thought at first that it might have been one of their test systems misfiring! Discussing different ways to tell if a signal that they see in the detector is a real signal or some kind of noise. Signal was just barely too weak to be detected with the initial interferometers.
11:19: "What does this mean for prevalence of gravitational waves sources? Do they happen more often than you thought or was it just dumb luck?" K.T. is referring to a paper - expect possibly multiple events per year. Instrument sensitivity can still be improved by a factor of 3.
11:21: Russian reporter asking about collaborations and what the next stage will be - space based interferometers? (Applause in the room here at GSFC - there are people who work on LISA here.) Concept of doing gravitational wave detection with interferometers has been around for a while, but it took many, many years for the technology to catch up - also crediting Russian work from 1962. Space based detector: funding trouble, now handed over to the Europeans, trying to fix. Will look at different sources and will solve some of the noise problems.
11:27: "What does this detection tell you about the conditions in the universe at the time that this merger occurred?" Large stellar mass black holes. Electromagnetic counterpart was not expected (no X-ray detection). Frequency response of the interferometer determines the size of the objects that you can detect.
11:30: "What sorts of inner workings can these waveforms probe?" Discussing simulations, analysis, uncertainty. Thanking the people at the supercomputing centers.
11:33: "What does this mean on earth and will it being us closer to time travel?" Laughter. Better understanding of how warped spacetime behaves in the nonlinear regime. Not likely to lead to time travel.
11:34: Role of Italian scientists and VIRGO? Analysis was jointly done, anxiously waiting for VIRGO to come online.

And we've switched over to local questions here - some of the authors of the paper are here and taking questions from the scientists.

Someone asked about the black hole spin parameters. Constraints are weak, but the spins are not extremely fast.

Progenitor information: low metallicity environment required.

Constraints on a gamma-ray burst signal at the same time? None detected, none expected. BH-neutron star mergers may produce one in the future.

Sensitivity relative to VIRGO? VIRGO will have 3/4 of the sensitivity in its final form, but it will take some time to ramp up to that. But it doesn't take much sensitivity from a third detector to greatly improve localization.

Dominant source of noise and rate-limiting source of noise? Seismic noise, definitely, at very low frequency (<50-60Hz). Above that, thermal noise in the mirror coatings is the limiting factor.

Technical question about how the detection happened that I only sort of understood. Part of the answer was that the "templates" for what kind of signals they were looking for in real time only included BH-NS mergers. Now BH-BH mergers are included also.

Possible other detections, but they are not ready to publish those yet.

Question about the "kick" that causes the merged black hole to take off in a particular direction. Not enough spin information to tell.

Relative sensitivity of LISA? S/N ratio for LISA will be better, but that's largely because the events LISA is sensitive to are intrinsically "louder".

Fermi, Swift, and the Palomar Transient Network did follow-up observations looking for an electromagnetic counterpart.

And I have to get back to work. I'll clean up this mess later and add some links to the context, but HOLY SHIT YOU GUYS.

Tl;dr: LIGO has detected a gravitational wave signal from the merger of two stellar mass black holes!




Edited to clean up the context section a bit and add a link to the LIGO collaboration's summary of the detection, which is very readable. Some of the actual papers are here (parameter estimation), here (astrophysics), and here (GR-specific), and this is the Phys. Rev. Letters paper - I haven't finished reading them, so don't ask me about anything in them yet!

 

!!!!!!!!! :D thank u for the liveblog, omg

 

Here's an article that covers the highlights of the press conference, including some video.

 

I am out in the field again! This time we are mapping rainforest sites in Gabon with a big collaboration of airborne radar and LiDAR instruments (UAVSAR from JPL, a German group from DLR with a multichannel radar instrument, and us, the LVIS LiDAR from Goddard Space Flight Center). We also have some people going out to take ground measurements at a few sites.

The radar groups are having a better time than we are. Their instruments go right through clouds, so they can fly any day there aren't active thunderstorms over the sites they want to map. Our laser does NOT penetrate clouds, and let me tell you there are a LOT of clouds in Gabon. The weather is also difficult-to-impossible to predict more than a few hours ahead. Today is our first flight. We'll see how it goes!

 

I really do. I feel like I'm in one of those identity swap movies sometimes - I don't know whose life as an International Traveler and Laser Scientist I accidentally stumbled into, but they can't have it back!

 

I can talk about just about everything related to my work (and I am delighted that you want to hear about it)! None of it's classified and all the data gets publicly released when we're done with the analysis. The only thing I can't do on this trip is take pictures of the plane. (The airport has two sides - the civilian and the military side - and we're being allowed to park the plane on the military side. So no photographs.)

Things about Gabon that I have learned from 4 days mostly spent in the hotel and the airport:

• This is one of the two rainy seasons in Gabon. It's hot and humid every day, mostly cloudy or hazy, punctuated by brief but intense rainstorms.
• The country is fairly rich, as African countries go, and politically stable. We're staying in the capital, Libreville. It seems reasonably safe? I went out and ran on the path along the water the other day and I got honked at a lot by passing cars, but nobody bothered me apart from that. The Gabon Estuary is right across the street from the hotel we're staying in and yesterday it was full of people swimming.
• Apparently there's a place south of here where the jungle goes all the way to the beach and hippos and elephants come out to play in the ocean! (Apparently it's also kind of hard to get there and I don't think I'll have a chance, but still!) There's a national park about a 45 minute drive away where you can hike in the rainforest and I'm determined to do that on the next down day. Gabon is mostly forested. Most of the sites we're mapping are either research stations or national parks.
• The national language is French. Fortunately, two people in our group speak fluent French, so we get around okay. (I am not one of the two. I wish I was so I could read all the stuff people chalk on the sidewalks.)
• HOLY MOTHER OF FUCK GETTING A VISA FOR GABON IS A PAIN IN THE ASS. The other 4 people on the LVIS team received their visas LITERALLY THE DAY WE LEFT. And we had official letters of invitation and filed our paperwork well in advance!
• Outside the tourist hotels and the airport, all transactions are conducted in cash.
• There are "taxi-buses" which are like the size of a VW bus and one said on the back "limit 19 passengers" and I spent a lot of time considering how one might cram 19 people into that vehicle.
• All the cars are manual transmissions. This was true in Chile too...I need to learn how to drive stick so I can drive the rental cars on these trips. If you're leaving the capital, you need a four wheel drive vehicle.
• For anything remotely business-related, you are expected to dress very formally - men in suits and ties, women in suits or dresses. I don't think our instrument technician actually owned a suit - he had to go out and buy one for the trip.
• Gabon's space agency, AGEOS, are the ones who invited us here, and there's a big joint media day planned. We'll be sharing all of our data with them. (This is the day we need the suits for.)

Today's a hard down day for the pilots, but the scientists don't get the day off - I'm working for at least the next few hours. I'll write up a post with some more information about the instrument and our operation when I get a chance. :)