Moon Watch

How to tell a Blood Moon from a Supermoon

Why does the Moon appear to change color, size, or brightness? Here's a little clarity.

Every four weeks, the Moon embarks on a brand new cycle around the Earth — an occasion marked by a new Moon. But if you look up at the night sky, you can barely see it.

At the beginning of its cycle, the Moon is on the same side of the Earth as the Sun, with its dark side facing our planet. As a result, it is almost invisible to us.

Over the course of its trip around Earth (27 days, 7 hours and 43 minutes), it changes: A small sliver of the Moon’s crescent gradually appears in our skies as it waxes to become a full Moon at the peak of its cycle. After that, it begins to wane into invisibility once more, before beginning anew, 29 and a half days after the preceding new Moon.

As it makes its journey, the Moon goes through eight different phases, each varying in brightness, visibility and size. But when it reaches the full Moon, things can get a little weird: It can appear enormous, super bright, or even look as though it had been drenched in blood.

NASA/Rami Daud

Inverse explains the science — and the folklore — behind each of these weird lunar phenomena. Prepare to become a Moon expert: With our guide, you will know exactly what our nightly visitor is going through.

Wolf Moon

The first time you see a full Moon during a new year is when you’re allowed to howl at it.

  • What is a Wolf Moon?

The Wolf Moon is the first full Moon of a new calendar year.

  • Why is it called a Wolf Moon?

This celestial event got its nickname from Native American tribes because it’s a time when wolves could allegedly be heard howling the most as there would be the least amount of food available during the farming season, according to EarthSky.

Wolves howled at full Moons in winter when there wasn't enough food around to eat.

NASA/Joel Kowsky
  • When is the Wolf Moon?

This year’s Wolf Moon was on January 10, and it marked the first of 13 full Moons for 2020. The next wolf Moon is on January 28, 2021.

A full Moon takes place once every 27 days, when the Earth is wedged between the Sun and the Moon at exactly opposite ends.

Blood Moon

The only thing spooky about a blood Moon is the intricate science behind why it gets to this color.

  • What is a Blood Moon?

A Blood Moon is a result of a total lunar eclipse. A total lunar eclipse is when the Earth is wedged right between the Sun and the Moon, blocking sunlight from illuminating the lunar surface, according to NASA.

A Blood Moon, captured in all its gory glory.

  • Why is it called a Blood Moon?

The Blood Moon gets its red color when it is orbiting through the Earth’s shadow, blocking the Sun’s light from illuminating it. When that happens, a little light from the Sun still reaches the Moon through the Earth’s atmosphere, bestowing it with a reddish hue.

That reddish color is actually a result of the atmosphere's chemical composition. As the Sun’s light pierces through it, air molecules filter out the blue light. The remaining light is often red, orange, or yellow.

  • When is the Blood Moon?

Blood Moons take place on two occasions every three years.

The last Blood Moon took place on January 20, 2019. The next Blood Moon is on May 26, 2021.

Harvest Moon

Before the dawn of electricity, farmers relied on a different light source to get their harvest done: Harvest Moons.

  • What is a Harvest Moon?

A Harvest Moon looks like a regular full Moon, but what makes it special is its timing. When the full Moon falls closest to Autumn, it is referred to as the Harvest Moon.

  • Why is it called a Harvest Moon?

It was given this name by Native Americans as farmers would rely on the bright light emanating from the Moon to work longer hours on their farms during corn harvest season, according to NASA.

A Harvest Moon rises over the mountains of Pasadena, California in September, 2016.

Doug Ellison/NASA
  • What does a Harvest Moon look like?

It is particularly bright and tends to rise earlier than usual. In the months leading up to Fall, a Moon will rise 50 minutes later each night but the few nights of the Harvest Moon, the Moon rises around the same time every day.

As a result, the Moon shows up in the sky right after the Sun sets.

  • When is the Harvest Moon?

Harvest Moons typically occur in the months of September or October.

This year's Harvest Moon will be on October 1, 2020, rising at 5:05 p.m. Eastern.


The reasons why this Moon is so super are that it is brighter and larger than a regular Moon.

A Supermoon shines when the full Moon happens to be closest to the Earth during its elliptic orbit. The proper astronomical term for it is perigean full Moon— referring to the closest point in the moon’s orbit called a perigee.

  • Why is it called a Supermoon?

A Supermoon appears as much as 30 percent brighter and 14 percent larger than normal because it is at the closest point to us on Earth.

A stellar example of a Supermoon.

  • When is the Supermoon?

This year, we will be treated to three Supermoons.

The first Supermoon of 2020 will take place on March 9, followed by one on April 8 and the last one on May 7.

Blue Moon

As the popular saying suggests, a Blue Moon is extremely rare.

  • What is a Blue Moon?

Despite its name, a Blue Moon is not actually blue in color.

A Blue Moon is a second full Moon in a calendar month, which only happens once every two and a half years. Typically, a month will only have on full Moon every 29 days but sometimes you can get two full Moons to fall within the same month.

A Blue Moon isn't actually blue, but the name stuck after a volcano turned the Moon blue in 1883.

  • Why is it called a Blue Moon?

The name dates back to 1883, when a volcano erupted in Indonesia, sending plumes towards Earth's upper atmosphere that turned the Moon to a blue color, according to NASA.

  • When is the Blue Moon?

A Blue Moon is a rare occurrence. But in 2020, we are in luck: A Blue Moon will take place on October 31, just in time for Halloween.

The last Blue Moon occurred on March 31, 2018 and the next one will occur on August 22, 2021.

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