Happy 230th Birthday, Enceladus, Our Solar System’s Greatest Hope For Life Beyond Earth
“It is still a complete unknown whether Earth is the only world in the Solar System to house any form of life: past or present. Venus and Mars may have been Earth-like for a billion years or more, and life could have arisen there early on. Frozen worlds with subsurface oceans, like Enceladus, Europa, Triton or Pluto, are completely different from Earth’s present environment, but have the same raw ingredients that could potentially lead to life as well.
Are water, energy, and the right molecules all we need for life to arise? Finding even the most basic organisms (or even the precursor components of organisms) anyplace else in the Universe would lead to a scientific revolution. A single discovered cell in the geysers of Enceladus would be the most momentous discovery of the 21st century. With the recent demise of Cassini, on the 230th anniversary of Enceladus’ discovery, the possibility of finding the incredible compels us to go back. May we be bold enough to make it so.”
On this date in 1789, William Herschel, armed with the most powerful telescope known to humanity at the time (you can get a lot of grant money when you discover the planet Uranus and name it after the King), discovered a relatively small moon of Saturn just 500 kilometers across: Enceladus. For some 200 years, Enceladus was never seen as more than a single pixel across, until the Voyager probes flew by it. What they revealed was a remarkable, unique world in all the Solar System. Now that the Cassini mission is complete, we can look back at all we know about this world, and all the signs point to a remarkable story: there’s a subsurface ocean, possibly suitable as a home for undersea life.
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.
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.
The Moon Will Swallow Saturn This Friday Morning, And You Can See The Event Yourself
“Almost all occultations that are visible from Earth occur between the Moon and another planet, but there’s something special about occultations of Saturn, owing to the extended, easily-visible nature of its ring system. The events themselves last longer as the planet disappears and reappears behind the Moon, as Saturn with its rings is a more extended sight than any other world as viewed from Earth.
There’s an entire astronomy enthusiast community devoted to observing occultations, and they’ve developed some very extensive resources that are freely available to the public. If you miss the occultation of Saturn on March 29, don’t fret; there’s another coming up on April 25, visible from Australia, New Zealand, and the western portion of South America.
When you see that pinprick of light approach the Moon, remember what it is you’re really looking at: the great ringed giant of our Solar System, preparing for its spectacular moment in the shade.”
On Friday morning, March 29, the Moon will appear to pass in front of Saturn, creating the spectacular and rare phenomenon of an occultation. For skywatchers across most of the world, it will simply appear as a close approach, as though the Moon had a satellite of its own for a brief time. But if you’re located in eastern South America or southern Africa, you might want to take a closer look for a chance at seeing the disappearance or reapparance of Saturn behind the Moon!
Here’s Your Proof That We Landed On The Moon, Steph Curry
“There are many different lines of evidence that point to humanity’s presence on the Moon. We landed there and can see the evidence, directly, when we look with the appropriate resolution. We have extraordinary amounts of evidence, ranging from eyewitness testimony to the data record tracking the missions to photographs documenting the trips, all supporting the fact that we landed and walked on the lunar surface. We have a slew of scientific instruments that were installed, took data, and a few of which can still be seen and used today. And finally, we’ve brought back lunar samples and learned about the Moon’s history, composition, and likely origin from it.
There are many ways to prove it, but the conclusion is inescapable: we really did land on the Moon, and we can validate it yet again by performing the right scientific test — through imaging or laser ranging —any time we want.”
There is no shame in being wrong. We must all remember that there are times where we did not know the things that now seem like obvious truths to us. But we all are capable of incorporating new information and drawing superior conclusions to the ones we drew initially.
Every few years, a new crop of young people become cognizant of an idea that has persisted for nearly 50 years now: the conspiracy that we never landed on the Moon. But if that’s what you thought might be the case, there would be ways of finding out. There would be things you could test, and evidence you could look to.
Triton, Not Pluto or Eris, Is The Kuiper Belt’s Largest World
“The result, today, is that the largest and most massive body ever to form in the Kuiper belt — 20% larger than Pluto; 29% more massive than Eris — is now Neptune’s largest moon: Triton. Today, Triton makes up 99.5% of the mass orbiting Neptune, an enormous departure from all the other giant planet systems we know of. The only explanation for its properties, especially its bizarre and unique orbit, is that Triton is a captured Kuiper belt object.
We often talk about icy moons with subsurface oceans as candidate worlds for life. We imagine large, distant, icy bodies as planets or dwarf planets in their own right. Triton was born not as a moon of Neptune, but as the largest and most massive Kuiper belt object to survive. You don’t cease to exist when you move locations, and neither did Triton. It’s the original king of the Kuiper belt, and its true origin story is a cosmic mystery that deserves to be solved.”
In October of 1846, just months after Neptune was discovered, a large moon was discovered around it: Triton. Today, Triton is a supremely unusual moon for a number of reasons, but the largest is that it rotates in the wrong direction. While Neptune orbits the Sun counterclockwise and spins counterclockwise on its tilted axis, Triton orbits in the opposite direction. The only way this could have happened is if it were a captured object. And that’s exactly what it looks like: a captured object from the Kuiper belt!
Rocky Planets May Only Get Moons From One Source: Giant Impacts
“If your gravity rises up to a point where you can pull yourself into hydrostatic equilibrium — a sphere if you’re static, an ellipsoid if you’re rotating — you cannot be pulled apart by tidal forces so easily. But you could, in principle, develop moons through three methods: initial formation from a protoplanetary disk, capturing another passing body through gravitational forces, or from the debris of a large collision.
While the gas giants display moons that appear to have arisen from all three, the rocky planets, including both major and minor planets, appear to obtain moons from collisions alone. It may be the case that the other options are viable but rare, and we simply have yet to discover them. But following the evidence we have today, perhaps Earth’s moon isn’t atypical after all. Until further notice, giant impacts are the only known way for rocky planets to gain moons.”
When we first visited the Moon and returned samples back to Earth for analysis, scientists were surprised to learn that the lunar surface was practically identical to Earth’s surface. The elements were the same; the isotope ratios were the same; the ages were the same. Unlike the other moons around other planets, the Earth’s moon appeared to be made out of the exact same material as our own world. This helped lead to the giant impact hypothesis as the origin of the Moon. Surprisingly, Mars’ moons and Pluto’s moons appear to have a similar origin: from a giant impact. Of all the planets and dwarf planets with moons, in fact, it looks like giant impacts explain them all.
“For almost every conceivable application to astronomy, going to the Moon is a vastly inferior location than simply being above the Earth’s atmosphere. The temperature extremes experienced everywhere on the Moon are an extraordinary challenge over and above any benefit you get from being on the Moon’s surface. Only in radio frequencies do the benefits of being on the lunar far side offer an opportunity for observing that we cannot get from either terrestrial or space-based observing.
Until the cost is either brought down or something we demonstrate we’re willing to pay, though, it is unlikely we’ll ever see a lunar telescope that’s superior to the other options. The Universe is out there, waiting for us to discover its secrets. When we decide a lunar radio array is worth it, we’ll advance tremendously in uncovering our cosmic origins.”
Practically everyone knows that our opportunities to view the Universe and learn about it, astronomically, are limited here on Earth. The atmosphere interferes with our ability to observe what’s out there, as do weather, human-created signals, and many other issues. We could go to space, of course, but many problems persist there as well. Perhaps putting a telescope on the far side of the Moon would hold the answer? As it turns out, the Moon is an even harsher environment, in many ways, than the depths of interplanetary space. There’s only one specific application that we know of, for radio astronomy, that offers a tremendous advantage. When we’re ready to invest and build a lunar array of radio telescopes, though, we’ll learn more about the early Universe than we ever have before.