“Even though the future seems far away, it is actually beginning right now.” -Mattie Stepanek
After another tremendous week here at Starts With A Bang, including one where I recorded a new podcast (look for it later this week on SoundCloud), it’s time to take a look back and review all that we’ve been through. From last Saturday through the past Friday, here’s what we saw:
- Are there different types of time and space? (for Ask Ethan),
- Deepest view of the Orion nebula reveals shocking discoveries (for Mostly Mute Monday),
- Forty years ago, we landed on Mars… and found life?,
- Apollo 11’s landing was 47 years ago today,
- Dark matter may be completely invisible, concludes world’s most sensitive search, and
- The most impossible technology from Star Trek.
There are some great new pieces coming up this week, but before tomorrow kicks them off, let’s hit the best of what you had to say on this edition of our comments of the week!
From Wow on the death of Steve Detweiler: “Arhythmia can set in no matter what your fitness level. Lack of fitness only gives other reasons for heart failure.”
As far as I knew, Steve was never a steroid user and wasn’t overdeveloped, just a healthy older man who did a lot of running and engaged in other athletic endeavors all throughout his life. His “claim to fame” athletically is that he wrestled (and pinned!) a much larger and more famous wrestler when he was in high school: someone named “Rick Fliehr,” who American audiences might know better as Ric Flair. They went to high school together; Steve was two years older and about 30-40 pounds lighter.
Steve’s legacy work, other than the Chodos-Detweiler paper, will likely be on using pulsar timing to detect very long-period gravitational waves. As Dave Reitze recounted:
“[Steve] theorized that you could detect gravitational waves from pulsar timing using radio astronomy. You’d have to look not for days or weeks but years, and even 5-10 years. If you had enough pulsars located over points in the sky, you should be able to look at a difference in timing from those pulsars. From that difference in timing, you could infer the existence of a gravitational wave background at extremely low frequency gravitational waves: in the nanoHertz range. This is an experiment going on right now. There are a number of these experiments working together, the NANOGrav collaboration in the United States, one in Europe called the European Pulsar Timing Array and one in Australia called the Parkes Pulsar Timing Array, and they all share data and work together. They are potentially on the verge of making a discovery of these low-frequency waves using a method that was first proposed by Steve Detweiler, so in some sense I think Steve was a real pioneer there.”
Good stuff from a good man and a great colleague. He’ll be missed by all who knew him.
From MobiusKlein on the expanding Universe: “But is the universe expanding for impractical purposes?”
What do you mean by “practical” when you consider this question? Do you mean things that originated on and that we interact with here on Earth? For those purposes, we cannot tell that the Universe is expanding. But you might as well say, then, when you walk around in your own backyard (or around your city block, if you live in a city), “the Earth is flat for all practical purposes.”
And you’d be right, in a very specific, very ignorant sense. You’re saying, in effect, “I’m not looking at enough information to make a data-driven decision, and therefore I can conclude whatever I want based on what I looked at.” So if you look at the light from galaxies other than our own, particularly if you start looking beyond our local group, you discover the expanding Universe, just as if you look at a large enough section of the Earth, you discover its curvature. So it depends on what you mean by practical.
From Chris Mannering on dwarf galaxy dark matter: “I’m trying to track down a comment I made in response to your idea for an explanation of why dwarf galaxies have higher dark-matter, namely that dwarf galaxies had more baryonic matter in the past but loses it from the galaxy at a faster rate then DM.”
Chris, did you mean this post here, where you commented “I don’t think this works because the corollaries are
– all small galaxies below some threshold, T, have the same dark matter mass, DMr, as one another respectively
– DMr = 5/4*T (assuming 4 parts DM to 1 part baryonic mass the dominant ratio above threshold T)”, and then “the second corollary should have been T = 5/4DMr”? That’s all I can find, but you may have been posting under one of the other names you sometimes post under, like Lucy Hibbs?
Oh yeah, I forgot to tell you all, when you sockpuppet, I notice. Bad form.
In any case, this is not my own personal theory, but a well accepted consequence of having galaxies of various masses (and various gravitational potentials) that then form stars and generate stellar winds and outward fluxes of particular magnitudes. When the velocity of the matter exceeds the escape velocity, good bye baryons!
From PJ on the infrared Orion Nebula: “Love the Trapezium photo. E & F stand out well, and it looks as if there are a few more cousins in that local group. Brilliant!”
It’s pretty interesting, because it was called “trapezium” because of the four bright members that make a trapezoid shape. Apparently — quite apparently — there are many more than four in there.
From Sinisa Lazarek on the discovery of more sub-stellar masses than we had previously thought: “Does this mean that the rough estimate of MACHOS present in the galaxy is about 10 times off? Thus we need less “exotics” DM?”
This question comes up every time someone finds more matter out there that hasn’t formed stars. The question is, “ooh, could this be some of the dark matter, and therefore could we need less dark matter than we thought, or maybe even none at all?” And the answer is always the same: NO. The reason it’s “no” is because we know the total amount of mass present in the Universe from a slew of observations: clustering, lensing, baryon acoustic oscillations, fluctuations in the cosmic microwave background and more. We get the same number from all of these observations: about 30%, plus or minus about 3%, of the total energy in the Universe is in the form of matter. Normal and dark matter combined. And we know, from again a slew of observations, including the CMB, the large-scale structure of the Universe and Big Bang Nucleosynthesis, that the total amount of normal matter in the Universe is around 5% of the total energy, plus or minus about 0.5%.
Now, there might be slightly more brown dwarfs and slightly less plasma; there might be slightly more planets and slightly less gas; there might be slightly more black holes and slightly less dust, etc. But the total amount of matter is well-known, and adding a little bit more of one type doesn’t change the total amount of dark matter at all.
From Denier on finding life on Mars: “Are you thinking it could be that long before we know because the next set of exobiology instruments being sent to Mars in the next few years (ExoMars Rover) are in the hands of the Russians and ESA?”
If ExoMars works, lands successfully and operates properly, it could find signs of past or present life on Mars. It would be amazing! But it’s really quite a limited piece of equipment, as is Mars Rover 2020 from NASA, which could figure out whether the methane vents on Mars are organic in nature or not. But these aren’t really capable of looking for life so much as organic molecules and biosignatures, which often have multiple confounding possible explanations.
In other words, they can provide “hints” of life, or under very rare circumstances, strong evidence for life. But they cannot say, “this is an organism of Martian origin and it is or was alive.” That technology is not aboard either rover. Which, honestly, is kind of a shame. That’s why I think it may take that long.
From Wow, arguing with Denier (and others) about the humans vs. robots argument in space: “Or fix the errors with nanobots, increase our DNA so that where cold blooded creatures use DNA information to code for development paths in different weathers (we mammals have temperature control and therefore jettisoned much of our genetic information as no longer necessary), add DNA to form proteins and other signals to repair damage to our cells from radiation.”
Yes, we can (and should!) send robots and other uncrewed missions to the outer worlds, into the hostile environment of space. We can learn so much, get a tremendous “bang for our buck,” put no human lives at risk, and build a robot much more hardy than a meatbag like us human beings.
But also… I want people to care about space. I want them to care about space exploration, about investing in this frontier, about dreaming of a better life for humanity on this world and beyond. And I don’t see us getting there. So when people say “human spaceflight,” I say yes. And when they say, “robotic missions,” I say yes. Yes to it all, and yes to a greater investment, a better future, and an interplanetary human civilization!
(Boy, election season is getting to me!)
From Elle H.C. on the LUX experiment: “What’s the difference with this one, and the one to detect proton decay, such as the kamiokande?”
If you want to watch for proton decay, you get a bunch of free protons together and look for decays that have energies of less than the mass of a single proton. You look for decay products like positrons and pions. And so you need individual protons, or hydrogen nuclei.
If you want to watch for a dark matter collision, you’re looking for a nuclear recoil, which means a massive particle colliding with a large-cross-sectional atomic nucleus that won’t interact any other way. Proton decay ain’t gonna happen in a large, bound-together nucleus, so the LUX experiment isn’t sensitive to that. That’s the biggest difference: recoil vs. decay. But other differences are that the WIMPs that LUX is looking for are in the ~10 GeV-3000 GeV range, while the proton decays are < 938 MeV. Different energies. But they both require big arrays of photomultiplier tubes and a big tank full of matter, so they have some similarities, too.
From Michael Shuster on the transporter: “Michio Kaku’s “Physics Of The Impossible” covers the transporter and some other familiar themes, and is a great read overall. BTW I believe he said that the transporter was a device of production convenience because of limited budget.”
I have nothing bad to say about the book, which you can check out at Amazon here. But that fact is not a case of “Kaku says” but rather a case of Gene Roddenberry himself (along with Stephen Whitfield) writing it in their book, “The Making Of Star Trek.” According to that book, Roddenberry originally wanted to have the crew depart the Enterprise via shuttlecraft and land on each world they wanted to visit. But this was unaffordable, and so the transporter was devised. Being made before computer animation, incidentally, a solution of glitter and water was agitated and filmed, allowing the “fade out/fade in” effect of transporters, and explaining why different colors were used for different civilizations’ technologies.
And finally, from Carl on a feasible (?) plan for a transporter: “I can readily envision development of teleporter technology. First, remote 3-D printing. Second, a baseline model for human tissue. Third, an architecture of a human (common nerve connections, hormone levels, etc).
Now we can print a human somewhere.
Next, we need to measure the important pieces of the teleporter subject. Brain connections, muscle mass, hormone levels.
Modify the base “human model” to match the measurements and remotely print someone who looks like and has the same memories as the teleporter subject.
Lastly (or maybe as part of the “measurement phase”), destroy the original.
Seems very likely to work IMO.”
Sure… except that’s not transporting you, that’s copying you, killing you, and trying to bring your clone to life. And if you could do it, it just might work! Rather than a Heisenberg compensator, you could set up a quantum computer with approximately 10^27-10^28 bits: the number of particles in your body. Right now, we’re up to 10^3 qubits. So just 24 more orders of magnitude to go! Who’s a fan of Moore’s law? Anyone?
Thanks for a great week, everyone, and I’ll see you back here tomorrow for more wonders and joys of the Universe!