What is Mercury in Retrograde, and Why Do We Blame Things On It?

NASA
NASA

Crashed computers, missed flights, tensions in your workplace—a person who subscribes to astrology would tell you to expect all this chaos and more when Mercury starts retrograding. In 2019, that means March 5-28, July 7-August 2, and October 31-November 20. But according to an astronomer, this common celestial phenomenon is no reason to stay cooped up at home for weeks at a time.

"We don't know of any physical mechanism that would cause things like power outages or personality changes in people," Dr. Mark Hammergren, an astronomer at Chicago's Adler Planetarium, tells Mental Floss. So if Mercury doesn’t throw business dealings and relationships out of whack when it appears to change direction in the sky, why are so many people convinced that it does?

The History of "Mercury in Retrograde"

Mercury retrograde—as it's technically called—was being written about in astrology circles as far back as the mid-18th century. The event was noted in British agricultural almanacs of the time, which farmers would read to sync their planting schedules to the patterns of the stars. During the spiritualism craze of the Victorian era, interest in astrology boomed, with many believing that the stars affected the Earth in a variety of (often inconvenient) ways. Late 19th-century publications like The Astrologer’s Magazine and The Science of the Stars connected Mercury retrograde with heavy rainfall. Characterizations of the happening as an "ill omen" also appeared in a handful of articles during that period, but its association with outright disaster wasn’t as prevalent then as it is today.

While other spiritualist hobbies like séances and crystal gazing gradually faded, astrology grew even more popular. By the 1970s, horoscopes were a newspaper mainstay and Mercury retrograde was a recurring player. Because the Roman god Mercury was said to govern travel, commerce, financial wealth, and communication, in astrological circles, Mercury the planet became linked to those matters as well.

"Don’t start anything when Mercury is retrograde," an April 1979 issue of The Baltimore Sun instructed its readers. "A large communications organization notes that magnetic storms, disrupting messages, are prolonged when Mercury appears to be going backwards. Mercury, of course, is the planet associated with communication." The power attributed to the event has become so overblown that today it's blamed for everything from digestive problems to broken washing machines.

What is Mercury Retrograde?

Though hysteria around Mercury retrograde is stronger than ever, there's still zero evidence that it's something we should worry about. Even the flimsiest explanations, like the idea that the gravitational pull from Mercury influences the water in our bodies in the same way that the moon controls the tides, are easily deflated by science. "A car 20 feet away from you will exert a stronger pull of gravity than the planet Mercury does," Dr. Hammergren says.

To understand how little Mercury retrograde impacts life on Earth, it helps to learn the physical process behind the phenomenon. When the planet nearest to the Sun is retrograde, it appears to move "backwards" (east to west rather than west to east) across the sky. This apparent reversal in Mercury's orbit is actually just an illusion to the people viewing it from Earth. Picture Mercury and Earth circling the Sun like cars on a racetrack. A year on Mercury is shorter than a year on Earth (88 Earth days compared to 365), which means Mercury experiences four years in the time it takes us to finish one solar loop.

When the planets are next to one another on the same side of the Sun, Mercury looks like it's moving east to those of us on Earth. But when Mercury overtakes Earth and continues its orbit, its straight trajectory seems to change course. According to Dr. Hammergren, it's just a trick of perspective. "Same thing if you were passing a car on a highway, maybe going a little bit faster than they are," he says. "They're not really going backwards, they just appear to be going backwards relative to your motion."

Embedded from GIFY

Earth's orbit isn't identical to that of any other planet in the solar system, which means that all the planets appear to move backwards at varying points in time. Planets farther from the Sun than Earth have even more noticeable retrograde patterns because they're visible at night. But thanks to astrology, it's Mercury's retrograde motion that incites dread every few months.

Dr. Hammergren blames the superstition attached to Mercury, and astrology as a whole, on confirmation bias: "[Believers] will say, 'Aha! See, there's a shake-up in my workplace because Mercury's retrograde.'" He urges people to review the past year and see if the periods of their lives when Mercury was retrograde were especially catastrophic. They'll likely find that misinterpreted messages and technical problems are fairly common throughout the year. But as Dr. Hammergren says, when things go wrong and Mercury isn't retrograde, "we don't get that hashtag. It's called Monday."

This piece originally ran in 2018.

What Do Those Recycling Symbols and Codes Mean?

iStock.com/ChrisSteer
iStock.com/ChrisSteer

Earth Day is here again, serving as an annual reminder of the need to reduce, reuse, and recycle our way to a better planet.

When it comes to the last part of that familiar three-”R” mantra, most people know enough to separate certain items from the rest of their garbage, but much of our modern recycling routine remains a mystery. From the recycling symbol itself to what those numbers on plastic containers actually mean, there's a lot you can learn from your trash before it becomes someone else's treasure.

An International Symbol With An Earthy Origin

The universal recycling symbol—three folded arrows that form a triangle, with the head of one arrow pointing to the tail of the next—was created in 1970 by University of Southern California student Gary Anderson as part of a contest tied to the very first Earth Day. Each arrow of the design represents one of the steps in the recycling process: collecting the recyclable goods after use, breaking them down and reforming them, and then packaging new products in the containers.

Originally designed as an inverted triangle, the symbol was later rotated to the pyramid-like orientation commonly used now.

The Number Game

The American Society of Plastics Industry first began using numbers inside the recycling symbols on plastic containers in 1988 as a way to assist with sorting them. The "Resin Identification Code" uses seven numbers to identify the type of synthetic material used to manufacture the container, with the higher numbers representing less commonly used plastics.

Here's a primer on each of the codes:

1. Polyethylene Terephthalate (PETE/PET)
Usually accompanied by the letters "PETE" or "PET," this resin is generally used for soda bottles and other containers for edible and non-edible goods. When it's not being used to manufacture containers, you might recognize it by another name: polyester. (Yes, it's the stuff that insulates your jackets.) It's also one of the most widely accepted forms of plastic in curbside recycling programs, though the amount of useable material available for new products after breaking down this plastic is relatively small.

2. High Density Polyethylene (HDPE)
The second most widely used resin for plastic bottles, HDPE is a stiff, strong material with a high resistance to chemicals, which has made it the go-to plastic for food items like milk and juice, as well as household cleaners and trash bags. It's also easy to break down in the recycling process and easy to reform, making it one of the most efficient consumer plastics. Most curbside recycling programs have no problem with accepting products made from this plastic.

3. Polyvinyl Chloride (PVC)
First discovered in the 19th century, PVC is commonly used in building materials today—especially pipes and plumbing material—due to its strength and chemical resistance (although it's occasionally used for some household products). It has a nasty habit of releasing highly carcinogenic toxins into the atmosphere when it's burned, so recycling is a significantly less appealing option for PVC disposal, and it's usually not accepted by curbside recycling programs.

4. Low Density Polyethylene (LDPE)
This plastic is becoming more common today, especially for manufacturing squeeze bottles and grocery bags. Plastics made from LDPE are usually very strong, and they're regularly used as sealants because of this quality. While they weren't included in curbside recycling programs at first, plastics made from LDPE are now becoming more commonly accepted.

5. Polypropylene (PP)
Regarded as one of the “safest” plastics produced today, PP is generally used for squeezable bottles, bottle caps, and straws. Along with LDPE, it's also used for food-storage containers that can be reused over time. It has an extremely high melting point, so it's one of the best consumer plastics for items that will be exposed to heat. Like LDPE, it's becoming more common for curbside recycling programs to accept items made from this plastic.

6. Polystyrene (PS)
More commonly known as styrofoam, this type of plastic is not only notoriously difficult to recycle, but it's also been shown to leach dangerous toxins over time into anything packaged in it—and even greater amounts of toxins when it's burned. This is the resin usually found in disposable serving trays, egg cartons, and cups, and it's rarely accept by curbside recycling programs due to the danger it poses and the difficulty of recycling it. Basically, this is the worst of the bunch.

7. Everything Else
There are countless other plastics, but very few of them are easily recycled in curbside programs, making this category the catch-all for everything that could conceivably be broken down and reformed, but might be better off reused or reformed in some way that doesn't require a chemical process. This category encompasses everything from bulletproof material to those large water jugs on office coolers, and is rarely included in curbside recycling programs.

Safety In Numbers

For anyone wondering which plastics are safe to reuse in their current form, it's widely accepted that HDPE (2), LDPE (4), and PE (5) can be reused multiple times for edible items, as they're generally resistant to chemicals, haven't been shown to degrade, and don't leach dangerous substances into their contents.

This story first ran in 2013.

What Do the Terms on Energy-Saving Light Bulbs Mean?

Scott Olson, Getty Images
Scott Olson, Getty Images

There's a reason your parents used to scold you for not turning off a light when you left a room. According to the U.S. Department of Energy, an average American household uses up to 5 percent of their total energy expenditure on lighting. Living rooms get flooded with light. Dining rooms and dens are full of lighting accents. Motion lights, hallway lights, bathroom vanity lights, lamps—we like our lives to be nice and bright.

Fortunately, energy-saving lighting sources have largely replaced the conventional incandescent bulbs that once used up a substantial amount of power. Those bulbs heated up a coil, or filament, of tungsten wire that gave off light. Roughly 90 percent of the energy they passed on was in the form of heat, which siphoned off energy and kept utility bills inflated. Today's bulbs brighten without the waste. That's the good news. The bad? The varieties of bulbs can be confusing. If you've ever been lost in the fixtures section of the hardware store, here's a quick primer on what these terms mean.

Halogen Incandescent:

These are incandescent light bulbs that contain a halogen gas-filled capsule around the filament to help increase energy efficiency. While cheaper to operate than a conventional incandescent bulb—they use 25 to 30 percent less energy—they don't produce as much of a cost savings as other options. On the plus side, they reach full brightness immediately. Other choices may take time to warm up.

Compact Florescent Lamp (CFL):

When you see a coiled light bulb, it’s likely to be a CFL, which is simply a downsized version of the tubular florescent lighting seen in commercial spaces. Instead of an electric current traveling through a filament like in an incandescent bulb, the current goes through a tube containing argon and mercury vapor. The resulting ultraviolet light activates phosphor inside the tube, which emits light. It uses one-third of the energy of a halogen incandescent. The downside? They can take a little time to warm up, especially if used outdoors. They also contain mercury, a potential health hazard if the bulb breaks. (See the "mercury" entry below.)

Light Emitting Diode (LED):

This type of bulb uses a semiconductor to convert electricity into light. In addition to being energy-efficient, they usually last eight to 25 times longer than halogen incandescent bulbs and four to eight times longer than CFLs—perhaps as long as 18 to 46 years. You'll probably pay more up front, but the expense is offset by their durability. Most LEDs are compatible with dimming switches, too. Most CFLs aren't, so if that's important to you, you'll want to stick with LED.

Energy Star:

A bulb with an Energy Star label was evaluated by a third party to make sure its energy-saving claims are accurate, and they'll typically have a longer warranty than bulbs without the endorsement.

But what about the "nutritional label" style information box that appears on light bulb packaging? Let's take a closer look.

An example of a label that appears on energy-efficient light bulb packaging is pictured
Federal Trade Commission

Brightness:

You have probably inferred that brightness refers to the light output given off by a bulb. This is measured in lumens and rounded off to the nearest five. (A bulb will never be 822 lumens. It's 820.) The higher the number, the brighter the bulb. Since you're probably used to shopping by wattage, consider that a bulb with 800 lumens is roughly the equivalent of a 60-watt incandescent. A 1100 lumen bulb will resemble a 75-watt bulb.

Estimated Energy Cost:

This is a rough estimate of much it will cost an average household to operate the bulb. What's average? The wattage of the bulb is calculated with three hours of daily operation at a cost of 11 cents per kilowatt. Your actual cost will go up or down whether you use it more or less or pay your energy supplier a different amount.

Life:

This is how long the bulb is expected to last based on the same usage estimated for the energy cost and rounded to the nearest tenth of a year.

Light Appearance:

This refers to the color temperature of the bulb measured in Kelvin, a temperature scale measuring light color. The range is from 2600 K (yellow and warm) to 6600 K (blue and cool). Bright white is about 3500 K. You should probably avoid anything above 3000 K for any interior room.

Energy Used:

This is how much energy the bulb will require and is measured in watts. The lower the wattage, the cheaper it costs to operate. This is where the energy savings materializes, as a 10-watt LED bulb may give off as much light as an old 60-watt incandescent.

Color Rendering Index (CRI):

It's not on all bulb packaging, but if you see it, it refers to how accurate colors will appear under the bulb's light on a scale of 0 to 100. Halogen incandescent bulbs score high. CFLs and LEDs aren't quite as accurate, though they may still get the job done. Try to get a high CRI if you'll be using the bulbs in a bathroom, as skin tone can appear off with lower CRI numbers.

Mercury:

You might see some CFL bulb packaging with a mercury disclosure. This isn't an issue if the bulb remains intact, but if it breaks, it might release potentially hazardous mercury vapor and the introduce the very small possibility of mercury poisoning. Avoid using CFL bulbs in kids' rooms if there's potential for knocking over a lamp or light. Broken bulbs that contain mercury should be cleaned up by following Environmental Protection Agency guidelines—picked up with tape, not vacuumed—and disposed of properly. Old bulbs should be recycled.

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