Virgo
Virgo is the largest of the 12 zodiac constellations. Spica, shining white in the southern sky on spring nights, is your signpost, and beyond it lie swarms of galaxies tens of millions of light-years away.
| Latin name | Virgo |
|---|---|
| Abbreviation | Vir |
| Brightest star | Spica (mag 1.0) |
| Best seen | Spring–early summer evenings (Northern Hemisphere) |
| Astrological dates | August 23 – September 22 |
| Sun actually passes | September 17 – October 30 |
| Stars used by Planetica | 2,703 |
How to find it
Virgo is well placed in the evening sky from April to June, and in early May it sits in the south after dusk. The constellation is huge, but apart from Spica most of its stars are 3rd–4th magnitude, so it's best to find Spica first and work outward from there.
To find Spica, use the Big Dipper. Follow the curve of the Dipper's handle and keep going: first you reach Arcturus in Boötes, a bright orange star, and continuing along the same curve you'll meet Spica shining blue-white in the south. Just remember: "arc to Arcturus, then spike to Spica."
Spica forms the "Spring Triangle" with Arcturus and Denebola in Leo. Northwest of Spica, stars spread out in a rough Y shape; these are the goddess's body and arms. Using Porrima, near where the Y branches, as your reference point makes the figure much easier to trace.
The myth: goddesses of harvest and justice
There are several stories about who Virgo is. The best known says she is Demeter, goddess of grain and farming, or her daughter Persephone. When Hades, god of the underworld, carried Persephone away, Demeter was so grief-stricken that she stopped tending the earth, and nothing would grow. In the end, Persephone was allowed to spend part of each year in the underworld and the rest with her mother, and that's how the seasons came to be. The star marking the ear of wheat in the goddess's hand is Spica, which means "ear of grain" in Latin.
In another story, Virgo is Astraea, goddess of justice. When an age came in which people quarreled and grew greedy, Astraea, the last of the gods to remain on Earth, finally left for the sky. The neighboring constellation Libra is seen as the scales of justice she carried.
In the East Asian 28 lunar mansions, Spica is the determinative star of the first mansion, the Horn (角宿), representing the horn of the Azure Dragon that guards the east. The next mansion, the Neck (亢宿), is also in Virgo.
Main stars
| Name | Apparent magnitude | Distance (approx., ly) | Notes |
|---|---|---|---|
| Spica (Alpha) | 1.0 | ~250 | A binary of two hot blue-white stars orbiting each other about every 4 days. |
| Porrima (Gamma) | 2.7 | ~38 | A binary of two similar stars with an orbit of about 169 years. |
| Vindemiatrix (Epsilon) | 2.8 | ~110 | A yellow giant whose name means "the grape-harvesting woman." |
| Delta Virginis | 3.4 | ~200 | A red giant on the inner side of the Y shape. |
| Zavijava (Beta) | 3.6 | ~36 | A star of a type similar to the Sun, and relatively nearby. |
In the sky between Denebola and Vindemiatrix lies the Virgo Cluster, about 54 million light-years away. It's an enormous group of more than 1,000 galaxies, and the giant elliptical galaxy M87 at its center is where, in 2019, humanity first imaged the shadow of a black hole. West of Spica, about 30 million light-years away, is the Sombrero Galaxy (M104), which looks like a wide-brimmed hat.
Birthday sign dates: two different answers
In astrology, Virgo runs from August 23 to September 22. But for most of that period, the real Sun is in Leo. The Sun actually passes through the Virgo constellation from about September 17 to October 30. At about 44 days, that's the longest the Sun spends in any zodiac constellation.
The first reason for the difference is precession. Earth's axis wobbles like a spinning top over a cycle of about 26,000 years, so the vernal equinox point moves west by about 1 degree every 72 years. Interestingly, this effect was first discovered in the 2nd century BC by the Greek astronomer Hipparchus, while comparing the position of Spica with older records. The astrological signs divide the ecliptic into 30-degree slices from the equinox point based on the reference of about 2,000 years ago, so the roughly one month of drift built up since then remains.
The second reason is that the constellation boundaries set by the International Astronomical Union (IAU) in 1930 cover different areas. Virgo occupies the widest stretch of the ecliptic. The dates can vary by about a day from year to year.
In Planetica
If your birthday's astrological sign is Virgo, Planetica places your planetary system next to a real star inside the Virgo constellation. Candidate stars are those in the HYG catalog within about 3,000 light-years of Earth and inside the IAU boundaries of Virgo, 2,703 in all. Because the constellation is so big, it has the most candidates of any zodiac constellation.
One of them is picked at random, and your system sits about 1–6 light-years from it. "Twin systems" from people with the same name and birthday all sit in Virgo, but each next to a different star.
Planetica also shows which constellation the Sun was really in on your birthday. For example, someone born on September 5 is a Virgo in astrology, but on that day the Sun was actually in Leo.
Fun facts
- Virgo is the second-largest of the 88 constellations, after Hydra.
- Today, the Sun is in Virgo at the September equinox.
- Virgo contains 3C 273, the first quasar to be identified, in 1963. Although it's about 2.4 billion light-years away, it's bright enough to look like a star in a telescope.
Other constellations
Create your own planetary system
Enter a name and a birthday to get a one-of-a-kind planetary system, placed next to a real star in your birthday constellation.