Why Does Mars Appear To Have Smoke Plumes In Its Atmosphere?
“On Earth, such plumes typically indicate one of two things: fires or volcanic eruptions. Without carbon-based material or copious amounts of available oxygen, we can rule out fire. Mars possesses the Solar System’s largest volcano in Olympus Mons, but it appears to be extinct. Although there is some circumstantial evidence that Mars may be volcanically active, we’ve never witnessed an eruption. Instead, these plumes are a simple atmospheric phenomenon: clouds.”
Have you ever seen a picture of Mars that displayed a feature that appeared to be an enormous smoke plume rising up from its surface? It isn’t a dust devil, as even though Mars has those, they don’t look like this. It isn’t a volcanic eruption, as even though Mars has multiple enormous volcanoes, they’re not active at this time. And it definitely isn’t fire from a Martian civilization, as Mars doesn’t even have the right atmospheric constituents to make a fire like we can on Earth.
Instead, it’s simply a cloud, albeit a type of cloud that can extend for many hundreds of kilometers around the Martian globe. Come find out how it forms today!
Ask Ethan: Can We Really Get A Universe From Nothing?
“One concept bothers me. Perhaps you can help. I see it in used many places, but never really explained. “A universe from Nothing” and the concept of negative gravity. As I learned my Newtonian physics, you could put the zero point of the gravitational potential anywhere, only differences mattered. However Newtonian physics never deals with situations where matter is created… Can you help solidify this for me, preferably on [a] conceptual level, maybe with a little calculation detail?”
You’ve very likely heard two counterintuitive things about the Universe before. One of them is that the Universe arose from nothing, and this defies our intuition about how it’s impossible to get something from nothing. The second is that we have four fundamental forces in the Universe: gravity, electromagnetism, and the strong and weak nuclear forces. So how, then, do we account for the fact that the Universe’s expansion is accelerating? Isn’t this clearly evidence for a fifth force, one with negative gravity?
Guess what? These two counterintuitive aspects of reality are related. If you understand them both, you’re one step closer to making sense of the Universe.
Starts With A Bang Podcast #46: Experimental Particle Searches
We know that there’s more to the Universe than we presently know. As successful as the Standard Model may be, it cannot describe everything we observe to be true about the Universe. Neutrinos oscillate from one flavor into another, and must have a non-zero mass, but we don’t understand why or how. Dark matter has an overwhelming suite of astrophysical evidence that points towards its existence, but we have no direct evidence for the type of particle it might be.
What do we do about these puzzles? We perform the best experiments we can to try and probe, identify, and constrain the novel physics that might be responsible for these unexplained phenomena.
This month, I’m so pleased to chat with Doctor Laura Manenti, postdoctoral research associate at NYU Abu Dhabi and a researcher on the XENON1T and the Proto-DUNE experiments. Take a dive into the world of experimental particle physics on the latest Starts With A Bang podcast!
Everyone Missed An Apollo 11 Mistake, And It Almost Killed The Astronauts Returning To Earth
“Fortunately for everyone, they did get lucky. During the technical debriefing in the aftermath of Apollo 11, the fly-by of the Service Module past the Command Module was noted by Buzz Aldrin, who also reported on the Service Module’s rotation, which was far in excess of the design parameters. Engineer Gary Johnson hand-drew schematics for rewiring the Apollo Service Module’s jettison controller, and the changes were made just after the next flight: Apollo 12.
Those first four crewed trips to the Moon — Apollo 8, 10, 11 and 12 — could have all ended in potential disaster. If the Service Module had collided with the Command Module, a re-entry disaster similar to Space Shuttle Columbia could have occurred just as the USA was taking the conclusive steps of the Space Race.”
The flight plan for Apollo 11 was straightforward, if not quite simple. Follow the same trajectory to the Moon that Apollo 8 and Apollo 10 undertook, then successfully enter lunar orbit, launch the Lunar Module, descend to the surface and land softly, perform the scheduled EVA, then ascend back to the Command and Service Module, return to Earth, jettison the Service Module, re-enter, and deploy the parachute to successfully splash down in the Pacific Ocean. Only uncovered well after the mission, there was a huge flaw: the Service Module wasn’t programmed to jettison properly! If things had gone differently, the Command Module could have been damaged, and would have burned up in the atmosphere, killing all on board.
Come learn about the Apollo 11 mistake that Armstrong, Aldrin, and Collins were lucky to survive!
What Makes Something A Planet, According To An Astrophysicist?
“A dolphin may look like a fish, but it’s really a mammal. Similarly, the composition of an object is not the only factor in classifying it: its evolutionary history is inextricably related to its properties. Scientists will likely continue to argue over how to best classify all of these worlds, but it’s not just astronomers and planetary scientists who have a stake in this. In the quest to make organizational sense of the Universe, we have to confront it with the full suite of our knowledge.
Although many will disagree, moons, asteroids, Kuiper belt and Oort cloud objects are fascinating objects just as worthy of study as modern-day planets are. They may even be better candidates for life than many of the true planets are. But each object’s properties are inextricably related to the entirety of its formation history. When we try to classify the full suite of what we’re finding, we must not be misled by appearances alone.”
You’ve heard about the IAU’s definition, where in order to be a planet, you must pull yourself into hydrostatic equilibrium, orbit the Sun and nothing else, and gravitationally clear your orbit. You’ve also heard about the controversial new definition from geophysical/planetary science arguments, that planets should be based on their ability to pull themselves into a spheroidal shape alone.
Well, what about a third way: defining planets (and a whole classification scheme) based on astrophysical concerns alone? It’s time to start thinking about it!
Our Generation Is Not Getting A Moonshot, And This Is The Reason Why
“We could take equally bold steps today if we wanted to. There are literally thousands upon thousands of astronomers, physicists, engineers, technicians, computer scientists, hardware designers, rocket builders, habitat designers, and many other skilled professionals who would love to participate in a moonshot for a new generation: a generation that grew up where crewed spaceflight beyond low-Earth orbit was only a historical memory.
Instead of investing a substantial amount of resources in truly reaching towards new frontiers, we’re delegating them to uncrewed, robotic space probes. Sure, the amount of scientific information we can get out of them is much higher for a much lower cost, but getting the most bang-for-our-buck isn’t why we push the frontiers of knowledge. Instead, we’re taking baby steps where great strides are called for.”
Have you ever dreamed of traveling to another world? Even if you yourself aren’t game for the journey, have you dreamed of humanity achieving that goal? For most of us alive today, we have never lived during a time where human beings were present anyplace beyond low-Earth orbit. Unless something dramatically changes, that will likely remain true for the remainder of the century. Humans aren’t headed to the Moon, to Mars, to a satellite world in the outer Solar System, or to an interstellar destination unless we seriously take the initiative to re-invest in basic research and development. Until we start stably allocating resources, personnel, and R&D priorities towards these ends, we’re going to remain stuck here on Earth.
Read this if you want to get motivated towards changing the course of human civilization for the better.
You Must Not Trust Experiments That Claim The Existence Of Parallel Universes
“Any time you get a positive signal from an experiment, you cannot simply take that signal at face value. Signals can only be understood in relation to the noise background of the experiment, which is a combination of every other physical process that contributes to the result. Unless you quantify that background and understand the source of everything that your final signal is composed of, you cannot hope to conclude you’ve discovered a new phenomenon in nature.
Science progresses one experiment at a time, and it’s always the full suite of evidence that must be considered in evaluating our theories at any given time. But there is no greater false flag than an experiment pointing to a new signal extracted against a poorly understood background. In the endeavor of pushing our scientific frontiers, this is the one area that demands the highest level of skeptical scrutiny. Mirror matter and even a mirror Universe might be real, but if you want to make that extraordinary claim, you’d better make sure your evidence is equally extraordinary.”
Have you heard that mirror-matter might be real, and existing in an alternate, dark reality that connects to our own? In theoretical physics, you have to have just the right combination of extraordinary skepticism of new ideas while simultaneously being open to them. In experimental physics, you search for ways to probe the limits of what’s presently known while looking for new signals that might herald the existence of some new type of addition to nature. There has been a lot of publicity, recently, about an experiment at Oak Ridge National Laboratory that could be a window into the mirror Universe. And indeed, it could.
But it could also be a window into exactly how easy it is to fool ourselves in experimental physics if we don’t carefully quantify our background. Don’t believe the results unless they clear this very, very high bar.
This One Species Of Animal Proves That The Moon Can Affect Biological Evolution
“The combined effects of the Moon and Sun create two tidal bulges around Earth, yielding high tides and low tides twice daily. When the Sun, Earth, and Moon all align, we get spring tides: the highest high tides possible. Tidal extremes occur during new and full Moons, with twice the magnitude of intermediate-phase neap tides. One terrestrial animal, the grunion, has uniquely adapted to take advantage of this lunar-induced phenomenon.”
There’s a species of animal out there that is absolutely reliant on the Moon for its reproductive success. The grunion, found along the pacific and baja coasts of North America, mates in an interesting fashion. The females come onto shore during high tides, where they bury the lower halves of their bodies in the sand until they stick up vertically, where they lay their eggs. The males then wrap around them, depositing sperm in an attempt to fertilize them. Now, here’s the fun thing: the eggs must remain on dry land for 10-11 days to incubate, meaning that the grunion can only do this during the highest high tides: spring tides.
Remarkably, because of our Moon’s properties and the combined tidal effects of the Moon and Sun, this enables the grunion to be an evolutionary success! Come get the full story here.
Ask Ethan: What Does ‘Truth’ Mean To A Scientist?
“I was speaking to a friend [who’s] an economic analyst, and his personal definition of a truth was when something’s 51%+ likely to happen… In science, do you ever truly accept anything as a truth, and if so, on what grounds do you typically decide its worthy of being called “true”?“
You might be used to the colloquial way we speak about things being true. It’s either true or it’s false. The truth is something that’s absolute, and something that’s untrue is either a lie, an ignorant statement, or something that’s simply not right. But in science, what we speak of as a scientific truth isn’t absolute at all.
All scientific truths are nothing more than provisional: they are our best approximations of reality. They have a range of validity over which they can be applied to give quantitatively correct predictions, and that range is finite and limited. Step outside of it, and you’ll find exactly where that scientific truth breaks down. When that happens, don’t despair, but rejoice!
You’ve found the limits to your truth, and can aspire to supersede it with an even better approximation of reality. Come get the real word on truth today!
Yes, Virtual Particles Can Have Real, Observable Effects
“Now that the effect of vacuum birefringence has been observed — and by association, the physical impact of the virtual particles in the quantum vacuum — we can attempt to confirm it even further with more precise quantitative measurements. The way to do that is to measure RX J1856.5-3754 in the X-rays, and measuring the polarization of X-ray light.
While we don’t have a space telescope capable of measuring X-ray polarization right now, one of them is in the works: the ESA’s Athena mission. Unlike the ~15% polarization observed by the VLT in the wavelengths it probes, X-rays should be fully polarized, displaying right around an 100% effect. Athena is currently slated for launch in 2028, and could deliver this confirmation for not just one but many neutron stars. It’s another victory for the unintuitive, but undeniably fascinating, quantum Universe.”
If you think about empty space at a quantum level, you’ll find that it isn’t so empty, after all. Due to the inherent effects of quantum uncertainty, particle/antiparticle pairs pop into and out of existence continuously, including electrically charged particles. If you look at the quantum vacuum in the presence of a strong enough external magnetic field, the positive and negative particles, even though they’re only virtual particles, will move differently, and therefore will affect the real particles that pass through them differently than if there were no magnetic field. This leads to a real, observable signal that can be seen in space: around neutron stars!
Heisenberg first predicted this in 1936, and today, we know it’s true. Get the story of the first observable effect of vacuum birefringence today.