How You Instagram Can Reveal Whether or Not You’re Depressed, Study Says


How you Instagram might reveal more about you than just what you did last weekend. One study found that certain Instagram photos can predict the markers of depression, as New York Magazine's Select All reports. And it's not the first study to link social media use and mental illness.

The study, in EPJ Data Science, looked at almost 44,000 posts from 166 people (71 of them depressed) using color analysis, metadata, and face detection software. (While less than 200 people isn’t a big enough number to really cement these findings, they at least analyzed a whole lot of brunch pics.) They found machine learning could successfully distinguish between the behavior of people diagnosed with depression and those with a clean bill of mental health by looking at the Instagram filter type of photos, the setting, whether or not there were people, color, brightness, and how many “likes” and comments it got. They also looked at how often people used the app and how often they posted.

The researchers’ Instagram model worked the majority of the time to correctly identify depression, even in posts made before the researchers diagnosed the person’s mental health status. Compare that to general practitioners' rates for correctly diagnosing depressed patients, which studies have found hover around 42 percent.

Depressed people tended to post darker photos, often using Instagram’s black-and-white Inkwell filter. They received more comments, but fewer likes on their posts. They tended to post photos of faces, but typically fewer faces than non-depressed users (social isolation is often linked to depression). By contrast, healthy people loved Valencia, which lightens images, and tended to get more likes.

Loving a black-and-white photo doesn't necessarily mean you're depressed. Maybe you’re just trying out your best Ansel Adams impression. But given the outsized role social media plays in modern life, it might be able to provide doctors with insights into patients' inner thoughts and feelings that they might not otherwise be privy to.

Other studies, too, have found that technology use can provide a window into people's souls, mental health and all. Research has found that unhappy people use their smartphones to cope with negative feelings, linking increased phone usage to anxiety and depression. A 2015 study found that smartphones could predict depression by tracking how often and where people moved.

In some cases, though, social media seems to play an active role in making people unhappy, rather than simply revealing their existing unhappiness. A 2017 study of 5000 people found that the more time people spent using Facebook, the worse their sense of well-being. (And that's even before you start talking about reading the news.) Other surveys have found that for teenagers, Instagram and Snapchat usage are associated with low self-esteem, bullying, and more.

But even if obsessively Instagram is making you unhappy in the first place, how you use social media could be an important factor for doctors to consider when evaluating mental health. It's hard to open up to people about depressive thoughts, especially if it's a medical professional you only see once a year. You might tell your doctor you feel fine, but be more honest about your inner darkness on Instagram—whether you realize it or not. So although you probably don’t want to hand over your social media history to your medical providers on a regular basis, it could provide a useful way to screen patients who aren't able to fully convey their mental health issues.

Does Sound Travel Faster or Slower in Space?


Viktor T. Toth:

It is often said that sound doesn’t travel in space. And it is true … in empty space. Sound is pressure waves, that is, propagating changes in pressure. In the absence of pressure, there can be no pressure waves, so there is no sound.

But space is is not completely empty and not completely devoid of pressure. Hence, it carries sound. But not in a manner that would match our everyday experience.

For instance, if you were to put a speaker in interstellar space, its membrane may be moving back and forth, but it would be exceedingly rare for it to hit even a single atom or molecule. Hence, it would fail to transfer any noticeable sound energy to the thin interstellar medium. Even the somewhat denser interplanetary medium is too rarefied for sound to transfer efficiently from human scale objects; this is why astronauts cannot yell to each other during spacewalks. And just as it is impossible to transfer normal sound energy to this medium, it will also not transmit it efficiently, since its atoms and molecules are too far apart, and they just don’t bounce into each other that often. Any “normal” sound is attenuated to nothingness.

However, if you were to make your speaker a million times bigger, and let its membrane move a million times more slowly, it would be able to transfer sound energy more efficiently even to that thin medium. And that energy would propagate in the form of (tiny) changes in the (already very tiny) pressure of the interstellar medium, i.e., it would be sound.

So yes, sound can travel in the intergalactic, interstellar, interplanetary medium, and very, very low frequency sound (many octaves below anything you could possibly hear) plays an important role in the formation of structures (galaxies, solar systems). In fact, this is the mechanism through which a contracting cloud of gas can shed its excess kinetic energy and turn into something compact, such as a star.

How fast do such sounds travel, you ask? Why, there is no set speed. The general rule is that for a so-called perfect fluid (a medium that is characterized by its density and pressure, but has no viscosity or stresses) the square of the speed of sound is the ratio of the medium’s pressure to its energy density. The speed of sound, therefore, can be anything between 0 (for a pressureless medium, which does not carry sound) to the speed of light divided by the square root of three (for a very hot, so-called ultrarelativistic gas).

This post originally appeared on Quora. Click here to view.

How Fossil Fuel Use Is Making Carbon Dating Less Accurate Wedzinga Wedzinga

The scientific process of carbon dating has been used to determine the age of Ötzi the Iceman, seeds found in King Tutankhamun’s tomb, and many other archaeological finds under 60,000 years old. However, as SciShow points out in a recent episode, the excessive use of fossil fuels is making that method less reliable.

Carbon dating, also called radiocarbon or C-14 dating, involves analyzing the ratio of two isotopes of carbon: C-14 (a radioactive form of carbon that decays over time) and C-12 (a more stable form). By analyzing that ratio in a given object compared to a living organism, archaeologists, paleontologists, and other scientists can get a pretty clear idea of how old that first object is. However, as more and more fossil fuels are burned, more carbon dioxide is released into the environment. In turn, this releases more of another isotope, called C-12, which changes the ratio of carbon isotopes in the atmosphere and skews the carbon dating analysis. This phenomenon is called the Suess effect, and it’s been well-documented since the ‘70s. SciShow notes that the atmospheric carbon ratio has changed in the past, but it wasn’t anything drastic.

A recent study published in Nature Communications demonstrates the concept. Writing in The Conversation, the study authors suggest that volcanoes “can lie about their age." Ancient volcanic eruptions can be dated by comparing the “wiggly trace” of C-14 found in trees killed in the eruption to the reference "wiggle" of C-14 in the atmosphere. (This process is actually called wiggle-match dating.) But this method “is not valid if carbon dioxide gas from the volcano is affecting a tree’s version of the wiggle,” researchers write.

According to another paper cited by SciShow, we're adding so much C-12 to the atmosphere at the current rate of fossil fuel usage that by 2050 brand-new materials will seem like they're 1000 years old. Some scientists have suggested that levels of C-13 (a more stable isotope) be taken into account while doing carbon dating, but that’s only a stopgap measure. The real challenge will be to reduce our dependence on fossil fuels.

For more on how radiocarbon dating is becoming less predictable, check out SciShow’s video below.