We’ve officially entered the era of nothing but teases for how important the Avengers 4 official title is. Paul Feig still wants to do a sequel to his Ghostbusters movie. An unlikely source reveals another Deadpool 2 character. Plus, more footage from Solo: A Star Wars Story and Jurassic World: Fallen Kingdom. Spoilers, away!

Maleficent 2

Variety reports Michelle Pfeiffer is in talks to play a major role in the sequel. If a deal is reached, she’ll play a currently-mysterious Queen.

The MCU

In an interview with the Associated Press, Kevin Feige revealed he’s already had meetings for MCU films not expected to see release until the year 2025. Because when you’re breaking box office records left and right, the ride never stops.

We’re always thinking ahead. Just when people think they can pin us down, we go somewhere else and that’s going to happen again after Infinity War in the build-up to the next Avengers film. And we had meetings earlier today about 2024 and 2025.

Avengers 4

Speaking with Bustle, Anthony Russo stated the secret title of Avengers 4 “speaks to the heart of the story.”

We do have a name for it, we’re just not announcing it. And I think we came to that name fairly early in the development process. It speaks to the heart of the story.

Annabelle 3

According to Entertainment Weekly, Annabelle writer Gary Dauberman is set to make his directorial debut with a third movie in the popular haunted doll franchise.

Ghostbusters 2

In an interview with Yahoo! Movies, Paul Feig stated he’s still interested in making a sequel to Ghostbusters: Answer the Call.

We would love to; it’s really up to the studio to want to do it. We had so much fun making that movie. The movie’s just really built an audience in the two years since it’s been out. I get contacted every day by people who are such fans of it, and so many women who are inspired by seeing women in science. I will go to my grave so proud of that movie, and so proud of what that cast did in that film.

Deadpool 2

Peter W., the breakout character from the Deadpool 2 trailer (who may or may not be comic book secret agent Pete Wisdom), has been tweeting photos of fellow X-Force members Domino, Bedlam, and Shatterstar, as well as debuting Bill Skarsgård as the acid-spitting mutant, Zeitgeist.

Deadpool also made a surprise appearance on Hugh Jackman’s Twitter feed, as he is wont to do.

Incredibles 2

There’s a ton of new footage in the recently released Japanese-dub trailer.

Solo: A Star Wars Story

Lando invites you to buckle up in the latest TV spot.

Hereditary

Toni Collette loses her cool in the new TV spot for Hereditary.

Jurassic World: Fallen Kingdom

“Genetic power has been unleashed,” according to Dr. Ian Malcolm in the latest TV spot.

Titans

Heroic Hollywood reports actress Conor Leslie has been cast in the role of Donna Troy/Wonder Girl.

Elsewhere, Minka Kelly posted a set video giving us a new look at Hawk & Dove... albeit with some slight modifications.

We also have the first set photo of Robin in full costume.

Watchmen

That Hashtag Show has casting calls for characters named Looking Glass, Panda, and Pirate Jenny, among others.

Angela Abraham: African-American female cop. Independent and intelligent, she’s also a realist. She’s married to Cal, with whom she has a daughter and is fiercely protective of them both.

Cal Abraham: African-American male who is the stay-at-home husband of Angela. While he seems at home as the king of his castle and being a loving husband and father, it’s clear his past has a different story to tell.

Looking Glass: A good looking cop, the native Oklahoman isn’t simple as his rural accent makes him appear to be. A top interrogator and behavioral scientist, he may also be a bit of a sociopath.

Panda: An ethnic desk cop, he’s cynical and tough and puts his job first. Not a friend to many, he uses comedy to keep people at bay.

Red Scare: Mafioso, track suit wearing cop. His Russian accent lends to his abrasiveness.

Pirate Jenny: An androgynous and lustful bisexual cop, Jenny is an anarchist at heart.

Jane Crawford: The wife of the police chief, Judd, Jane is a veterinarian who’s sharper than her guarded persona lets on.

Old Man: A former cop who is still an imposing figure despite his age.

Agents of SHIELD

Adrian Pasdar goes full Graviton in the trailer for this week’s episode, “The One Who Will Save Us All.”

Arrow

The late Tommy Merlyn drops in on Oliver’s trial in pictures from this week’s episode, “Docket No. 11-19-41-73.” More available at TV Line.

Once Upon a Time

True love’s kiss turns out to be a total bust in the trailer for the penultimate episode of Once Upon a Time, “Is This Henry Mills?”

Westworld

A tiger stalks the park in the trailer for next week’s episode, “Survival.”

Fear the Walking Dead

Madison declines an offer for a weenie in the trailer for next week’s episode, “Buried,” which also sees a unique-looking zombie with a face full of porcupine quills.

The 100

The CW talks to Marie Avergeropouos about Octavia’s development in season five.

Stranger Things

Finally, a new video reveals season three of Stranger Things is now in production.

_{Banner art by Jim Cooke.}

Despite having sold its phones here for years, 2018 was supposed to be Huawei’s big coming out party in the U.S. At CES, I sat through a presentation about how Huawei was expanding into home wifi and had even signed Wonder Woman herself as the company’s new brand ambassador.

But then AT&T, Verizon, and Best Buy all backed out of or canceled deals to carry the company’s phones in retail stores; all while Huawei faced even greater pressure from U.S. intelligence. That left Huawei’s latest flagship phone—the P20 Pro—in a weird place, because instead of potentially being the first P-series phone to get sold in America, we’re left watching it thrive overseas with no hopes of a stateside release. And that’s a damn shame, because with a gorgeous design and an innovative triple camera setup, the P20 Pro is actually a pretty great device.

Even just looking at the specs, you can see where Huawei made a lot of smart decisions. Featuring a Kirin 970 processor, 6GB of RAM, and 128GB of storage as standard. (There’s no microSD expandability, but who really cares these days.) Meanwhile the dual SIM tray is a boon for frequent travelers. But P20 Pro’s real treat is its giant 4,000 mAh battery. On our battery rundown test, the P20 Pro lasted 11 hours and 36 minutes. That’s better than even the Pixel 2 XL (11:17), though still slightly short of the S9+’s time of 12:27, which remains the best time we’ve recorded yet this year.

Then there are other little things like the IR blaster embedded in the top edge of the device, which is feature that used to be quite common, but almost every phone maker has long abandoned. And as you’d expect from a phone of this caliber and price, you get IP67 water-resistance and some pleasantly powerful stereo speakers.

That said, the P20 Pro still has two big sticking points: the lack of a headphone jack and wireless charging. Being forced to use USB audio is something you can mull over yourself, you can either deal with it or you can’t. But no wireless charging is a strange omission considering the phone’s 900 euro price tag, which translates to around $1,100. Unlike last year’s P10, whose metal back made it difficult for the phone to play nice with wireless charging tech, the P20’s back is a big sheet of glass. For a phone this expensive, there’s really no excuse.

Perhaps Huawei’s plan was to dazzle users with one of sparkling colors. With an entrancing color shift from green to purple, Huawei’s signatureTwilight paint job looks like nothing else out there. But even in the standard blue of our review unit, the P20 Pro is just as sharp.

Now I know some people might take issue with Huawei’s use of a notch, but there really isn’t anything to complain about. Out of the box, the cut out for the P20 Pro 20-MP front-facing camera is pretty obvious. But if you’re not a fan, there’s an option in the display settings to mask the notch with black bars on either side. This gives you the ability to see your notifications and time, date, and battery like you would normally, but without having something protruding into the screen, and in my opinion, it’s the best blend of form and function.

But enough with all the dilly dallying, how bout those cameras? Sporting a 20-MP black-and-white camera, a massive 40-MP RGB camera, and a 8-MP camera with a 3X zoom, Huawei’s world-first camera arrangement has something for everyone.

Using the monochrome cam, even on something as simple as a black and white photo, the P20 Pro easily out shot the Galaxy S9 in gray scale mode. Frankly, it’s not even close, as the P20 Pro’s captured much better details and sharper edges versus the complete oversaturation seen in the S9’s pic. And these abilities aren’t relegated just to black-and-white shots either.

When using the 40-MP RGB camera, which is what the phone relies on most of the time, the P20 Pro uses the monochrome camera to help capture fine details, while the 40-MP camera concentrates on colors and everything else. On top of that, the P20 Pro’s 40-MP sensor uses a quad bayer filter which creates groups of four pixels and essentially combines them into one giant pixel, which lets the camera soak up a ton of light. So in the end, the phone spits out pictures that are just 10-MP in resolution, which are just slightly smaller than the 12-MP rear cameras in Pixel 2 XL and Galaxy S9, but not by much. And what you get in exchange for the loss in overall resolution is totally worth it.

Just take a look at how the S9 and P20 Pro snapped a pic of some plums. The S9’s shot isn’t bad, but the P20 Pro’s pic has it beat it almost every single way: sharpness, color, detail, you name it. The most obvious example is when you zoom in to look at the labels on the fruit. The barcode and lettering in the S9’s photo looks a little fuzzy, while in the P20 Pro’s pic, lines are bold and crisp. Now I must point out that the P20 Pro’s pic is probably a little oversharpened, but it still beats the S9’s version hands down.

And in low-light things get even better, because that quad bayer arrangement lets the P20 Pro hang with the S9, despite having a smaller f/1.7 aperture compared to the S9’s industry-leading f/1.5 iris.

But then, Huawei went the extra step and created an incredible low-light mode that captures four-second long-exposure shots that can be taken even while hand held. That’s right, no tripod needed. Now normally, this would cause streaks all over the place (and if people move around too fast, you still get a little motion blur), but on the P20 Pro, you get a sort of specialized nighttime HDR shots that often look shockingly good.

Finally, there’s that 8-MP camera with a 3x optical zoom, which is 1x more than what you get on the iPhone X or Galaxy S9. So when you need that little extra reach, like say when you’re at a ballgame or concert, the P20 Pro has got you covered there too.

However, the P20 Pro’s cameras aren’t without their flaws. Like the Mate 10 Pro. the P20 Pro has the ability to use object recognition to identify things like dogs, plants, and food, or scenes like landscape and blue sky, and then use that info to fine tune the camera settings for optimal results. The problem is that it seems in the six moths since Huawei’s last iteration, the company may have pushed its algorithms a little too far.

For example, when I snapped very typical shot of some flowers, the P20 Pro pumped up saturation of greens and yellows to an absurd degree, to the point where the pic almost looks neon. You can also kind of see in the clock photo above, where the blue-sky mode does a little bit too good of a job making those blues stand out. Thankfully, disabling the auto-tuning is as simple as hitting the little “x” next to the object recognition tag in the camera app.

But here’s the real tragedy, Huawei isn’t selling the P20 Pro in the states, and based on pressure from seemingly everly level of the government, there’s almost no chance that will change. In fact, just four months in, it seems Huawei may have already decided to reconsider is expansion into the US, in favor of refocusing its efforts on more welcoming markets like Europe and Asia. That means like all those fancy cheeses made in France and elsewhere, or genuine Kobe beef from Japan, the Huawei P20 Pro is a delicacy only available overseas. That’s pretty depressing, because this is an exciting, innovative phone that gives Apple, Samsung, and Google’s best some actual competition. And the worst part about all this, is that we really only have ourselves to blame.

README

• The P20 Pro isn’t available in the US, and Huawei has no intentions of bringing it over.
  
• While sometimes you have to fiddle around with the settings or veto the aggressive AI, the P20 Pro’s triple cam setup is no joke.
  
• Battery life is fantastic, with the P20 Pro lasting over 11.5 hours on our test.
  
• Huawei’s EMUI 8 is easy enough to use, but I still don’t think it looks quite right.
  
• There’s no headphone jack, wireless charging, or microSD card slot, though there is support for dual SIMs.
  

SPEC DUMP

EMUI 8.1 running on Android Oreo 8.1 • Kirin 970 processor • 6GB of RAM • 128GB of storage • 6.1-inch 18:9 2240 x 1080 OLED display • 4,000 mAh battery • 24-MP front cam • rear 20-MP monochrome cam • rear 40-MP RGB cam • 8-MP telephoto cam with 3x optical zoom •USB 3.1 Type-C port • NFC • 6.10 x 2.91 x 0.31 inches • 6.35 ounces

It’s an orgy of geometry, here on Earth. You got all kinds of shapes: Squares, trapezoids, even the occasional rhombus. Apples, desk-chairs, and dandelions—just an abundance of shape-having stuff. Outer space, in contrast, is minimally decorated: asteroids, stars, planets, galaxies. Big-picture stuff. We know the Earth is round—or, at least, most of us do—but what about the other stuff? What shapes are twirling around up there, and why do they look like that?

For this week’s Giz Asks, we posed those questions to a number of physicists and astronomers, who detailed the handful of shapes that exist in space and explained how, exactly, those shapes took form. There are really two processes at play here: one, the massive rotations, collisions and collapses that, over millions of years, have given form to outer space; and, two, the brief history of our efforts to understand and label them.

Alyssa A. Goodman

Robert Wheeler Willson Professor of Applied Astronomy and Co-Director for Science at the Radcliffe Institute for Advanced Study at Harvard University

There are basically three important shapes that objects take in space. One is round, like a ball. One is a disc, like a frisbee—a very flat, round thing. And then the other one is generally a mess—not a regular shape, like a pyramid or a cube or something like that. A comet is good example of a mess.

The older something is, the more likely it is to have a distinct shape. In other words, a sphere or a disc takes a long time to format. One of the reasons that comets are so irregular is that they’re relatively new. Some part of them might be very old, but they get hit a lot as they form—they form out of sticking things together, little tiny dust particles, which themselves are irregular.

Fred Whipple has this great expression where he calls comets “dirty snowballs.” If you imagine a kid making a really bad snowball, that’s the shape of a comet—dirt and rocks and little pieces of asphalt. You don’t usually wind up making an absolutely perfect sphere unless you work on it for a while.

Planets are things that have forms due to something that came from a disc—when a star forms, the material that doesn’t go into the star forms into a frisbee-like disc, or more accurately a pancake-like disc.

The reason that you see those kinds of discs so often—the disc that’s going to form planets around a star, and also disc-like galaxies—has to do with angular momentum. When you have something spinning, there are forces on it that make it want to pull out to the sides and expand. The analogy that is usually used is the figure skater. The figure skater’s arms want to fly out to the side—that’s centrifugal force on her arms. Or think of an amusement park ride, where you stick to the sides of a very fast moving cylinder. That kind of centrifugal force makes things want to move outwards perpendicular to the axis around which something is spinning.

Even the Earth is not a perfect sphere. The Earth is a slightly smushed sphere: its diameter at its equator is slightly bigger than its diameter through the north and south pole. But what I’m talking about is something very, very extreme—if you spin really fast, and you don’t have any kind of structure stability from stuff like rock, which the Earth does, you make things into a pretty flat disc as they try to collapse. The same way we’re held to the Earth by gravity, any stuff can be held to any other stuff by gravity, so those things have a center of mass, and they want to move towards [that] mass.

So if you’re not spinning very much, then that would result in a sphere, because that force is [symmetric] to a point, which is the center of mass. But if you spin very fast, then there’s competition between the outward force from the spin—centrifugal force—the outward spin force and then the inward gravity and the spin one is just [plain] perpendicular to the rotation and the gravity is symmetric, so you wind up with disc. So that’s why a lot of galaxies look like discs, and a lot of material around forming stars look like discs.

Instability can make those discs into interesting patterns. Some of them turn into spiral galaxies, some of them fragment or break up in other ways.

Planets tend to be spherical, so why they’re not themselves discs is a very good question. In some cases we know the answer to that and in other cases we don’t. But they’re not spinning so fast that they would be crushed into discs. The Earth would have to be spinning really really fast in order for it to be more than just a tiny bit squished by its own rotations. There’s an outside crust that’s hard to smush. Gaseous planets like Jupiter or Saturn are spherical, but that’s because there’s a lot of pressure from the gas that makes them up. There’s a competition between various forces. Basically, if spin wins, you wind up with a disc. And if other things win, you wind up with a sphere. And if you haven’t had a lot of time, you wind up with something that wants to be a sphere but it’s a mess.

There’s a kind of galaxy called an elliptical galaxy, which are not spheres, but they’re not discs or messes, either. They’re kind of like an egg. And that happens from mergers from other galaxies coming together and adding up to almost a mess but not quite. They kind of try to become a sphere. You could almost say that an elliptical galaxy, if you left it alone for the longest possible time, might become something like a sphere, but many of them are already practically the age of the universe, so we don’t have enough time to know what would happen to them.

Meredith Hughes

Assistant Professor, Astronomy, Wesleyan University

Planetary systems like ours are flat, with planets orbiting around in concentric orbits all going the same direction rather than buzzing around like bees in a hive.

Star and planet formation happens when dense pieces of molecular clouds collapse under the influence of gravity—essentially, when they become dense enough that gravity can overcome the cloud’s natural pressure. Molecular clouds are wreathing, smoky mixtures of gas and dust spread throughout our galaxy, and the collapse isolates one part of the cloud and shrinks it down to a relatively tiny size. That process of taking something that is slowly wreathing on large scales and shrinking it is exactly like what happens when a figure skater starts a slow spin and then pulls in her arms: the closer her arms get to her body, the faster she spins. The smaller the cloud gets, the faster it spins.

At that point, you have gravity being sticky and pulling things together, and you have angular momentum causing a major spin. Another situation in which you have a sticky substance that starts to spin is something you have probably done in your own kitchen: making a pizza. In a collapsing cloud, just like when you spin sticky pizza dough, the combination of spin and stickiness flattens the material into a disk- or pizza-like shape. We call these disks of leftover cloud material orbiting around young stars “protoplanetary disks,” because that leftover material from the cloud forms the building blocks for planets that will eventually orbit the star. Since the material starts off in a disk, which has a preferred plane and spin direction, the planets that form out of the disk generally retain that flat shape and the same spin direction—both in terms of which way they orbit around the star, and in terms of how they orbit on their axis. That’s why, when you look at orbits in the Solar System, all of the planets are located in a fairly flat plane, they all orbit the Sun in the same direction, and almost all of them rotate on their axes in the same direction (Venus and Uranus are the two exceptions—we think they got smacked by some other large body shortly after they formed that knocked them a bit off-kilter). This is an old idea, dating back to Kant and Laplace, but it’s one of the fundamental insights that forms the basis of our modern-day understanding of the planet formation process.

Richard Townsend

Associate Professor, Astronomy, University of Wisconsin-Madison

Most things in space—in particular, stars, planets, black holes and large asteroids —are spherical in shape, like a basketball. This is because the dominant force at the immense scales in space is gravity. For any sufficiently massive object, self-gravity—the gravitational pull of each part of the object on the other parts of the same object—tends to mold the object into the most compact form, and that happens to be a sphere. There are a couple of exceptions to this rule, however. If the mass of the object is not big enough to generate significant self-gravity, then other forces—for instance, structural forces arising from the rigid nature of solid matter—can counteract the gravity and produce a more complex shape. This is the reason why smaller asteroids, and also comets, are often not spherical; an example here is comet 67P/Churyumov-Gerasimenko, which was revealed by the Rosetta probe to have a peculiar rubber-duck shape. It’s also the reason why humans are not spherical!

Another exception arises if the object is rapidly spinning. Then, inertial effects from the rotation (what we think of as the ‘centrifugal force’ in everyday life) counteract the gravitational force in directions perpendicular to the rotation axis. This often results in an ‘oblate spheroid’ shape similar to M&M candy, or a disk-like shape. We can see the former in our own solar system: Jupiter and Saturn both spin rapidly with a rotation period close to 10 hours, and both are oblate spheroids rather than spheres. Likewise, the latter can be seen in the structure of many galaxies, including our own Milky Way (the appearance of the Milky Way, as a band of diffuse light on the night sky, is because we’re embedded inside the disk).

Jonathan Levine

Associate Professor, Physics, Colgate University

Many objects in space, like stars and planets, are quite nearly spheres. The sphere is the shape with the greatest symmetry; it’s no different in one direction than any other. Stars take this shape because the gravity pulling themselves together finds an equilibrium with the pressure of their hot gas pushing themselves outward. Both gravity and pressure are isotropic, meaning that they too are symmetric, and have no reason to prefer one direction over another. The sphere’s symmetry is demanded by the symmetry of the two balanced symmetric forces.

Earth is almost a sphere as well, but in Earth’s case the gravity that would tend to compact it is opposed by the strength of rock and water, rather than the pressure of hot gas as in the Sun. Still, the material strength of Earth’s constituents are nearly isotropic as well, so our planet is quite nearly spherical.

I say “almost” and “quite nearly” because many objects in space, from planets to galaxies, are partly flattened because of their rotation. Earth spins on its axis every day, so in addition to gravity and material strength, there is also a tendency for material to be flung outward, away from the spin axis, and to accumulate in the body’s equator plane. For this reason, Earth is about a dozen miles wider at the hips than it is tall. For Saturn, with its lower density and faster spin, the difference between its width and height is more like 15%. The Milky Way, for its part, is nearly 100 times wider than it is tall. In all cases, the spin breaks the symmetry between one direction (the axis of rotation) and all others.

Pedants might quibble about my saying that material tends to be flung outward while spinning, since this statement smacks of centrifugal forces, which their physics teachers assured them did not exist. However, these people can thank me (and centrifugal force) next time they eat pizza, rather than a saucy cheesy dough-ball.

Leslie Rogers

Assistant Professor, Astronomy and Astrophysics, University of Chicago

If an asteroid, moon, or planet is sufficiently massive, the force of its own gravity will be large enough to overcome the strength of the material from which the body is made, and the asteroid/moon/planet will be pulled into a rounded, nearly-spherical shape. Bodies made of rocky material will be gravitationally rounded if they’re larger than about ~450km in radius, while bodies made of weaker icy material will be pulled into a rounded shape if they’re larger than about ~200km in radius. Mimas, the “Death Star lookalike” moon of Saturn, is the smallest known gravitationally rounded body in the Solar System, having a radius of 198 km.

In fact, one of the requirements for a body in the Solar System to be defined a planet (according to the 2006 International Astronomical Union definition) is that it has sufficient mass to assume hydrostatic equilibrium (a nearly round shape).

Gravity would cause an isolated, non-rotating massive body to take on the shape of sphere. If the asteroid/moon/planet is rotating, it will take on the shape of an oblate ellipsoid that is flattened along the poles and bulges out at the equator. Due to rotational flattening, the radius of the Earth at the Equator is 21km larger than the radius of the Earth at the poles. Saturn is the most oblate planet in the Solar System, with its equatorial and polar radii differing by nearly 10%.

The presence of another mass (e.g., a star or a satellite) can also distort the shape of a planetary body due to tides. Because the force of gravity is stronger the closer one gets to a gravitating mass, the side of a planet that is closest to the other mass will feel a stronger gravitational pull than the most distant side. This has the effect of stretching the planet along the direction toward the other mass (star or satellite). It is tidal bulges on the Earth induced by the gravitational pull of the Moon that lead to the twice daily rise and fall of the ocean tides (which are especially prominent in the Bay of Fundy, near my hometown in Nova Scotia).

Pauline Bamby

Associate Professor, Physics and Astronomy, Western University

The shapes of things in space are due to competition between gravity, which wants to bring matter together; pressure, which wants to push matter apart, and rotation, which causes special directions within an object to be important.

Planets and stars are close to being spheres. All the matter within them exerts a gravitational pull on all the other matter, and the most efficient way to get the stuff as close together as possible is to arrange it in a sphere. Why doesn’t the gravity pull so hard that stars and planets collapse into smaller and smaller spheres and become a black hole? Because when the atoms within get close enough together, they push back against each other. That push back is another one reason planets aren’t quite spherical – the Earth isn’t perfectly smooth because the crust sticks together or folds up to make continents. The other reason planets and stars aren’t quite spherical is that they rotate: this squashes them a little so that they are fatter around the equator. For the Earth this results in a tiny difference between its radius at the poles and at the equator of about 0.2%; for other planets and some stars this difference can be much larger – about 10% for Saturn.

One of the ways we define an object as a planet is that its gravity pulls it into a sphere. The largest asteroids, like Vesta and Ceres, are also nearly-spherical. But smaller, “minor planets,” can be quite oddly-shaped, like anything from potatoes to footballs to dog bones. These shapes can depend on what the asteroid is made of and whether it has collided with other asteroids.

Galaxies are a slightly different story from stars and planets. Galaxies are so big that, unlike the atoms in a star, the stars inside a galaxy don’t generally get very close to one another. Gravity and the orbits of stars determine galaxies’ shapes, but getting to a final shape takes a very long time because the distances are so large. Left to their own devices, galaxies can be nearly-spherical, like planets and stars, or highly-flattened due to rotation—our Milky Way is one of these flattened spiral galaxies. Because they are so big, galaxies are more likely than stars or planets to collide! When galaxies get close to each other, their mutual gravity can pull out long tails or shells of stars and gas from their outskirts. If the galaxies are moving slowly enough to eventually merge, their shapes become quite lumpy and distorted—we affectionately call these “train wrecks”—until millions of years pass and gravity smooths everything out.

Rachel Bezanson

Observational Astronomer, University of Pittsburgh

Galaxies in the nearby Universe come in two basic types: flattened disk-like spirals, like our Milky Way, and rounder, more spherical, elliptical galaxies. Spiral galaxies will often have a nearly spherical bulge in the center such that their overall shapes would closely resemble two sunny-side up eggs pasted together on their flat edges. If you rank-order galaxies by the ratio of bulge to disk size, eventually you start to find galaxies with no obvious disk at all—which we call elliptical galaxies. These galaxies are rarely perfectly spherical, but are often “oblate spheroids,” or hamburger-shaped, with one axis slightly shorter than the others.

Of course, when we see galaxies in the sky, we see them projected onto 2-dimensions, so depending on the angle from which we are looking, we can see spiral galaxies as anything from very narrow lines, possibly with a round bulge, if we see them edge-on to perfectly circular if they are face-on. Elliptical galaxies will also exhibit a range of projected elongations (from fairly narrow ellipses to circles), but will be rounder on average than spiral galaxies.

In general, the shapes of galaxies reflect the orbits of the stars racing around inside of them. If you have many stars orbiting in an ordered fashion in the same plane, their paths will trace out a thin disk, like the disks found in spiral galaxies. Any time you have significant populations of stars that trace out orbits in a different plane those random motions will start to create rounder, more spherical shapes in three dimensions. These random or non-planar orbits are found in the round bulges of spiral galaxies and in elliptical galaxies. We think that most stars in the Universe form in disk-like structures, therefore all random orbits—and therefore rounder shapes—that we observe are caused by galaxy interactions and collisions. Therefore determining the shape of galaxies and the nature of their stellar orbits are instrumental to understanding their cosmic history.

Do you have a burning question forGiz Asks? Email us at tipbox@gizmodo.com.