We’ve all seen illustrations of the Solar System. They’re in our school textbooks, on posters, on websites, on t-shirts… in some cases they’re used to represent the word “science” itself (and for good reason.) But, for the most part, they’re all wrong. At least where scale is concerned.
Sure, you can show the Sun and planets in relative size to each other accurately. But then the actual distances between them will probably be way off.* And OK, you can outline the planets’ concentric orbits around the Sun to scale pretty easily. But then there’s no convenient way to make sure that the planets themselves would actually be visible. In order to achieve both, you have to leave the realm of convenience behind entirely and make a physical model that, were you to start with an Earth the size of a marble, would stretch for several miles (and that’s not even taking Pluto into consideration.)
This is exactly what filmmaker Wylie Overstreet and four of his friends did in 2014, spending a day and a half on a dry lake bed in Nevada where they measured out and set up a scale model of the Sun and planets (not including Pluto, don’t tell Alan Stern) including their respective circular orbits. They then shot time-lapse images of their illuminated cars driving around the orbits. The resulting video is educational, mesmerizing, beautiful, and overall a wonderful demonstration of the staggering scale of space in the Solar System.
I love anything that attempts to provide a sense of scale about the Solar System (see here and here for even more examples) and this one brings us down past the Sun, planets, and moons all the way to asteroid size — specifically asteroid 101955 Bennu, the target of the upcoming OSIRIS-REx mission.
Created by the OSIRIS-REx “321Science!” team, consisting of communicators, film and graphic arts students, teens, scientists, and engineers, the video shows some relative scales of our planet compared to the Sun, and also the actual size of asteroid Bennu in relation to some familiar human-made structures that we’re familiar with. (My personal take-away from this: Bennu — one of those “half grains of sand” — is a rather small target!)
A NASA New Frontiers mission, OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) will launch in Sept. 2016 on a two-year journey to the asteroid 101955 Bennu. Upon arrival OSIRIS-REx will map Bennu’s surface and also measure the Yarkovsky effect, by which asteroids’ trajectories can change over time due to the small force exerted by radiant heat.
Caught on camera by NASA’s Solar Dynamics Observatory, a prominence blazes hundreds of thousands of miles out from the Sun’s surface (i.e., photosphere) on May 27, 2014. The image above, seen in extreme ultraviolet wavelengths, shows a brief snapshot of the event with the column of solar plasma stretching nearly as far as the distance between Earth and the Moon.
Watch a video of the event below:
The video covers a span of about two hours.
Although it might look fiery in these images, a prominence isn’t flame — it’s powered by rising magnetic fields trapping and carrying the Sun’s superheated material up into the corona. And while this may not have been a unique or unusual event — or even particularly long-lived — it’s still an impressive reminder of the immense scale and energy of our home star!
Sometimes when I see data on sizes and distances in relation to stuff out in space, it’s hard to get a frame of reference, since those two categories tend to lean towards the super-big. But now, I’ve got a little help. Space enthusiast and software engineer Ciro Villa has brought some of these references closer to home with these fun graphics that provide accurate size ratios and proportions of objects in space compared to places on Earth.
Villa calls these graphics “hovering celestial objects” and while all of these scenarios are impossible in real life, he’s placed large asteroids and moons next to Earthly locations to provide a good frame of reference for dimensions. Please note that most of these objects have absolutely no chance of colliding with Earth as they are not anywhere near our neighborhood and are not expected to visit it either.
“My representations are is purely for illustrative purposes,” Villa said. “I have maintained the size ratios and proportions as accurately as possible just to demonstrate the dimensions. This is mostly a ‘fun’ exercise.”
For example, I regularly drive through the St. Louis, Missouri metro area, so I have a sense of how big it is. Above, Villa places Asteroid 243 Ida — which has an average diameter of 31.4 km (19.5 miles) — to hover right above St. Louis. 31 km is about the distance from East St. Louis, Illinois to Creve Coeur, Missouri, which are the generally accepted eastern and western borders of the St. Louis metro area. I could probably drive across Ida in about 30 minutes — if it’s not rush hour, that is!
To create these graphics, Villa uses Google Maps, NASA data and Gimp image editing software. Again, these graphics are for fun, but I really find them useful!
And Villa provided a caveat: “Please note that I am not a professional graphic artist, so I’m sure people are going to find plenty of imperfections in these depictions,” he said. “The important point I am trying to convey is mainly the size dimensions comparing with a known area of Earth.”
Here are more:
Here are a bigger pair of objects in comparison to an area of Eastern Texas and Western Arkansas. 90482 Orcus is a trans-Neptunian Kuiper belt object that is about 800 kilometers in diameter. Orcus has a fairly large moon orbiting it named Vanth, which is about 300 km in diameter.
This asteroid might pay Earth a close visit, but not for a couple of million years. Eros is the second largest NEO (Near Earth Object), with a diameter of approximately 34 kilometers, and here Villa imagines Eros centered over the VAB (Vehicle Assembly Building) at Cape Canaveral, covering the Cape area from approximately the southern end of the Canaveral National Seashore to the Pine Island Conservation area, with the VAB in about the middle, as the crow (or sandhill crane) flies.
While Eros is technically an NEO, it made one of its closest passes of Earth in 2012 of 16.6 million miles (26.7 million km) and won’t pass that close again until 2056. A look ahead with orbital mechanics suggests that Eros may move to an Earth-crossing orbit in about two million years, given the right perturbations by gravitational interactions.
And to show the scale of several moons in our Solar System, Villa made these comparisons:
“Deimos is about 15 kilometers across, so I have measured a portion of the city of Paris, France of about 5 Kilometers and properly scaled Deimos,” Villa said. “For added dramatics, I have purposely shown enough of Deimos hovering to show about 5 kilometers of Paris, to show some of the landmarks (notice the Eiffel tower). Had I decided to show all of Deimos, the scale would have been too large to recognize any of the landmarks of Paris.”
Continuing these imaginary montages, here is one of our favorite moons, Enceladus, with an approximate diameter of about 500 kilometers, seen drifting over Southern England. That’s about the same distance from Plymouth to Leigh-on-the-Sea in the UK.
This last one is a bit personal for Villa, since he lives in Florida. Here, Saturn’s moon Phoebe hangs over Central Florida. “Phoebe shares an approximate diameter of 200 kilometers with the central portion of the state,” Villa said, “and I wanted to ‘play’ with my imagination a bit!”
Measuring distance doesn’t sound like a very challenging thing to do — just pick your standard unit of choice and corresponding tool calibrated to it, and see how the numbers add up. Use a meter stick, a tape measure, or perhaps take a drive, and you can get a fairly accurate answer. But in astronomy, where the distances are vast and there’s no way to take measurements in person, how do scientists know how far this is from that and what’s going where?
Luckily there are ways to figure such things out, and the methods that astronomers use are surprisingly familiar to things we experience every day.
[/caption]The video above is shared by the Royal Observatory Greenwich and shows how geometry, physics and things called “standard candles” (brilliant!) allow scientists to measure distances on cosmic scales.
Just in time for the upcoming transit of Venus, an event which also allows for some important measurements to be made of distances in our solar system, the video is part of a series of free presentations the Observatory is currently giving regarding our place in the Universe and how astronomers over the centuries have measured how oh-so-far it really is from here to there.
Video credits: Design and direction: Richard Hogg Animation: Robert Milne, Ross Philips, Kwok Fung Lam Music and sound effects: George Demure Narration and Astro-smarts: Dr. Olivia Johnson Producer: Henry Holland