This logarithmic view of the Universe will blow your mind

It’s a long way from planet Earth to the Universe’s edge.

This artist’s conception shows a logarithmic view of the observable Universe. The Solar System gives way to the Milky Way, which gives way to nearby galaxies which then give way to the large-scale structure and the hot, dense plasma of the Big Bang at the outskirts. Each line-of-sight that we can observe contains all of these epochs, but the quest for the most distant observed object will not be complete until we’ve mapped out the entire Universe. With each passing new year, another few tens of thousands of galaxies potentially become visible.

Our tiny home world, seemingly massive, is merely 12,742 km (7,917 miles) across.

This image, taken from the International Space Station by astronaut Karen Nyberg in 2013, shows the two largest islands on the southern part of the Mascarene Plateau: Réunion, in the foreground, and Mauritius, partially covered by clouds. To see a human on Earth from the altitude of the ISS, a telescope the size of Hubble would be needed. The scale of a human is less than 1/5,000,000 the scale of Earth, but Earth is just a proverbial drop in the cosmic ocean, with a diameter of only a little over 10,000 kilometers.

We typically think linearly: where the Sun is ~10,000 times farther away than Earth’s diameter.

The orbits of the planets in the inner Solar System aren’t exactly circular, but they’re quite close, with Mercury and Mars having the biggest departures and the greatest ellipticities. In the mid-19th century, scientists began noticing departures in the motion of Mercury from the predictions of Newtonian gravity: the differences were small, but measurements were so accurate that the discrepancy couldn’t be ignored.

But cosmically, logarithmic scales — where each multiplicative factor of “10” defines another mark on our cosmic ruler — serve us far better.

The Earth, at nearly 13,000 kilometers (8,000 miles) in diameter, is tiny compared to the cosmic distances between the Earth-and-Moon or, more spectacularly, the Earth-and-Sun. But a logarithmic scale gives us a vastly different perspective, enabling us to reckon with disparate distance scales in a single visual image.

On a logarithmic scale, the Sun, Mercury, and Mars are practically equidistant.

The inner Solar System, including the planets, asteroids, gas giants, Kuiper belt, and more, is minuscule in scale when compared to the extent of the Oort Cloud. Sedna, the only large object with a very distant aphelion, may be part of the innermost portion of the inner Oort Cloud, but even that is disputed. On a linear scale, depicting the entire Solar System in a single image is incredibly limiting.

Another factor of ~10,000 in distance takes us to the Oort cloud.

In the Solar System, we typically measure distances in Astronomical Units (AU), where the Earth-Sun distance is 1 AU. Mercury and Mars are also about ~1 AU from Earth, with Saturn at ~10 AU, the Kuiper belt ending before ~100 AU, and the Oort cloud largely existing at ~10,000 AU. It’s an enormous distance on a linear scale, but only a small set of “factors of 10” away on a logarithmic one.

A short logarithmic jump takes us from the Solar System to the stars.

This long-exposure image captures a number of bright stars, star-forming regions, and the plane of the Milky Way above the southern hemisphere’s ALMA observatory. The nearest stars are only a few light-years away: less than a factor of 10 from the edge of the Oort cloud. But more distant stars and features, still visible with the naked human eye, can be tens of thousands of light-years away instead.

Many of the brightest stars in Earth’s skies are under 1,000 light-years away.

Many of the brightest nearby stars to Earth are members of the Orion arm, which itself is a minor spur of the larger, grander Perseus arm of the Milky Way. From the nearest stars, a few light-years away, to these arms, a few thousands of light-years away, represents only three factors of “10” on a logarithmic scale.

Another small logarithmic jump brings us to our nearest spiral arms.

Gaia’s all-sky view of our Milky Way Galaxy and neighboring galaxies. The maps show the total brightness and color of stars (top), the total density of stars (middle), and the interstellar dust that fills the Galaxy (bottom). Note how, on average, there are approximately ~10 million stars in each square degree, but that some regions, like the galactic plane or the galactic center, have stellar densities well above the overall average.

Beyond that lies the full Local Galactic Group.

The Perseus spiral arm leads into the full-scale Milky Way, with other galaxies in the Local Group lying only a single factor of “10” beyond the full-scale Milky Way. Another factor of 10 beyond that takes us to large galactic groups and even approaches the closest galaxy cluster.

Rapidly, neighboring galaxies become ubiquitous.

This illustrated map of our local supercluster, the Virgo supercluster, spans more than 100 million light-years and contains our Local Group, which has the Milky Way, Andromeda, Triangulum, and about ~60 smaller galaxies. The overdense regions gravitationally attract us, while the regions of below-average density effectively repel us relative to the average cosmic attraction. However, the individual groups-and-clusters are not gravitationally bound together and are receding from one another as dark energy dominates the cosmic expansion.

Subsequent cosmic steps reveal large-scale galaxy clustering.

There are only a few factors of “10” in logarithmic distance that separate the nearest galaxies, located a few hundred thousand to a few million light-years away, to large-scale clustering features on the scales of hundreds of millions or possibly one billion light-years. At these scales, the Universe’s largest bound features begin to come into view.

Eventually the largest structures of all are revealed: the great cosmic web.

Over time, gravitational interactions will turn a mostly uniform, equal-density Universe into one with large concentrations of matter and huge voids separating them. Because simulations are limited in the number of particles they can handle at once, the largest-scale cosmic simulations are inherently limited in their ability to resolve individual, early galaxies. However, the great underdense regions, the cosmic voids within our Universe, are well-understood.

Many of these features are only apparent: dark energy will tear these pseudostructures apart.

The largest features seen here, like “great walls” and “large quasar groups” may not be cosmologically bound structures, but rather apparent pseudostructures, where gravitation due to their cumulative masses will be insufficient to keep them bound. Dark energy, on the largest cosmic scales, will drive all things apart.

At the cosmic limits, the edges of time are revealed: the earliest moments after the hot Big Bang.

Our deepest galaxy surveys can reveal objects tens of billions of light years away, but even with ideal technology, there will be a large distance gap between the farthest galaxy and the Big Bang. At some point, our instrumentation simply cannot reveal them all, and the gap between the emission of the cosmic microwave background and the formation of the very first stars will finally be definitively revealed to us.

Thanks to artist Pablo Carlos Budassi for creating this brilliantly illustrated cosmic journey.

This vertically oriented logarithmic map of the Universe spans nearly 20 orders of magnitude, taking us from planet Earth to the edge of the visible Universe. Each large “mark” on the right side’s scale bar corresponds to an increase in distance scales by a factor of 10.

Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.