How can I see Venus?

You can see Venus in the sky at two times and locations:

  • in the early evening, shortly after sunset in the west or
  • the early morning, shortly before sunrise in the east. 

Venus orbits the Sun and moves from evening sky to morning sky and back again over the course of about 18 months. Venus makes beautiful sweeping motions in the sky that reveal secrets of the solar system.

See Venus, see the plane of the solar system

Solar system plane
The planets all orbit the sun in the same plane. Image not to scale.

All the planets in the solar system orbit the sun. All of the orbits line up in neatly nested concentric rings. And all of the rings are lined up with each other as if they are placed on a single surface together.

The orbits are all in the same plane. It’s like they are all marbles circling around the sun on the same giant plate. This is called the “ecliptic” and it is visible in the sky if you know how to find Venus.

Intersecting space planes

The “space plane” is not an airplane

The “plane” is a tool you can use to see the way things move in space. This “plane” is not an airplane, but a flat slice of space.

Here is an image of two intersecting planes. Imagine the blue plane is the earth’s surface and the brown plane is up-and-down from ground to sky.

Each object (and movement) in space creates a “plane,” an imaginary slice through physical space. The blue “plane” above looks like the surface of a pond, lake or ocean. A wall or roof of a house is a plane. A dinner plate is a plane. Stretch your arms out and spin in a circle and you have created a plane with your arms.

There are planes in space everywhere.

Your own personal space plane

You create a plane with your vision and balance. You can imagine a flat surface like the surface of a pool of water and your eyes are just above the waterline. This surface moves and tilts when you move your head.

Your head has two eyes that define your plane of vision. Also, your body is oriented to gravity because of your sense of balance – the “personal horizon” is the first plane for you to orient to. Your body naturally coordinates your visual sense with your sense of balance and gives us the sense of being located level on a surface. This is the “sense of horizon.”

A new horizon – choose a plane!

To get good at Physical Astronomy, we have to learn to coordinate our main “personal horizon” plane with other planes of the earth, moon, solar system, galaxy, and universe.

The earth for instance, has a lot of planes, the range of latitudes, the north and south poles, the Arctic and Antarctic circles, the equator, the tropics, a range of longitudes, the prime meridian, the international date line, the ecliptic, the galactic plane and more.

To keep things simple, let’s focus on just one other plane for now: the plane of the solar system. A wonderful thing will happen when you learn to link the plane of vision with the plane of the solar system. It’s pretty easy to do, and it’s a skill that gets better with practice.

The key to linking vision and solar system planes is to know that the plane of the solar system is visible as the ecliptic. One easy way to see the plane of the solar system is to see the bright inner planet Venus.

See Venus see the orbit of Venus in the western sky just after sunset. See how the line from Venus to the Sun defines the ecliptic.
See Venus and you can see the orbit of Venus

See Venus and the Orbit of Venus

Venus is closer to the Sun so we are able to see its entire orbit. Actually, we can’t quite see the entire orbit because sometimes it goes in front of the sun and sometimes it goes behind the sun.

We can see Venus in the early evening and in the early morning. Venus is visible in our sky when it is at the left and right extent of its orbit around the sun. We only see Venus in the sky when it is swooping around the left or right of the sun.

If you want to see the orbit of Venus and see the plane of the solar system you can do it! All you have to do is imagine a line connecting Venus to the Sun.

If you are looking at Venus early in the morning before sunrise or early in the evening before sunset, the process is the same. Imagine a line connecting Venus to the Sun; this is the ecliptic. Venus’s entire orbit covers roughly 1/4 of the sky.

Summary

We learned about two main planes in space: your personal horizon (which changes as the Earth carries you around the Sun) and the plane of the solar system: the ecliptic. 

By learning to visualize these two space planes, we can begin to experience the extremely large dimensions of space.

References

Venus information from In the Sky.

8 Ways to Find the North Star

Find the North Star

You can use these 8 ways to find the North Star (Polaris). These are all fun ways to find the North Star. The North Star is special because of its position in the starry sky.

Can you find the North Star in this image? It is the star that is closest to the middle of the concentric rings of star trails. This is a long exposure photograph of real stars as seen over the course of several hours during the night.
A long exposure photograph showing all of the other northern sky stars circling around the North Star. Image provided by ESO.

8 ways to find the North Star

  1. Look north and guess – you can find the North Star in a relatively dark region of the sky and there are not many other bright stars around it. If you are south of the equator, head north before you try to look for the North Star because you won’t be able to see it until you get the Earth out of the way.
  2. Use the Big Dipper cup stars as pointers. This is the classic way to find the North Star. The two stars of the Big Dipper cup are known as the “pointer stars” and they show you which star is the North Star. The North Star is about 5 lengths of the pointer stars away.
  3. Camera timelapse – ooh! I love timelapse. A great timelapse of the night sky is an unbeatable way to relax. By taking a timelapse of the starry sky you can detect the apparent motion of the stars. If your timelapse covers enough of the sky  (with a wide angle view) chances are that you will be able to identify the North Star because it is the star that moves the least.
  4. Phone app – grab a planetarium app like SkySafari. Almost every star app these days has a “Augmented Reality” view that you can use to find Polaris. Just use the AR method of holding the phoone up above your head and searching around or you can type the name of a star into the search box in the app.
  5. Observe the sky, patiently measuring the movement of every star. The one that moves the least is Polaris. This might take a long time because the stars move pretty slowly.
  6. Mark a known spot as your North Star viewing spot. This is easy to do with a product like the Star Spot. You can return to that spot any time of day or night  to sight the star – the North Star is always in the same place in the sky.
  7. The North Star is located in between the two easy-to-identify constellations The Big Dipper and Cassiopeia – the Queen.
  8. Memorize its color and the stars around it – this is easier than it sounds! Polaris is a yellow supergiant and has a faint yellow tint. Also, the North Star is located in a region of the Milky Way that has fewer stars so it is surrounded by dark areas of the night sky.
  9. A reader has suggested a 9th way! Create the Summer Diamond. Add a new triangle to the Summer Triangle asterism by using the North Star as a new point. Suggested to me in January 2023 by Peter Birren (Author of the wonderful Objects in the Heavens astronomy book) see below for an illustration. This method is most useful in the summer and early fall months because that is when the Summer Triangle is most visible.
Summer diamond asterism - find the North Star using the Summer triangle asterism as a marker.
Find the North Star using new asterism – the Summer Diamond. Proposed by Peter Birren.

The Standard way to find Polaris, aka the North Star

Here is the classic way to find the North Star! Use the pointer stars of the Big Dipper. This is a reliable method for finding the North Star that has been taught to generations.

Find the Big Dipper to find the North Star

Look at the two stars in the picture below. One is Dubhe – which is labeled a for alpha, and the other Merak – which is labeled b for beta. These form the outer lip of the Big Dipper’s cup. These two stars can be used to create an imaginary line to “point” at the North Star.

The distance from the pointer stars to the North Star is about 5 times the distance between Dubhe and Merak.

The North Star is shown in this image as a red dot labeled “Polaris.”

You can find the North Star using the two pointer stars of the Big Dipper (Dubhe and Merak) The North Star is also called Polaris and is part of the constellation Ursa Minor.
Use the two pointer stars of the Big Dipper to find the North Star (Polaris). Picture credit user Bonĉ source Wikipedia

These instructions work for the 80% of people who live in the northern hemisphere – anywhere north of the equator. For the 20% of people who live in the southern hemisphere the North Star is not visible because it is blocked by the Earth. As you move south toward the equator (and eventually move past the equator), the North Star gradually sinks lower in the sky until it stays completely below the northern horizon.

Click here to continue reading…

Where is the Sun?

Where is the Sun right now?

Can’t see the Sun? Maybe there is something blocking it. Here is a list of 10 surprising things that can block the Sun.

IMAGE of floating/flying things overhead (in roughly size order) that can block all or part of the SUN: Flying animals (Bugs, Birds/Flying Mammals), Flying objects (Drones/Balloons/Airplanes/Helicopters/Rockets/Bombs/Blimps), Smoke/Clouds, Spacecraft (Satellites/Space Stations/UFOs), Asteroids, Moon, Mercury, Venus, Earth.
Things that block the Sun.

Where is the Sun during the day? On a clear day, this is a very simple question. The Sun is “up there” in the sky – it’s a big, bright, fiery ball and it’s generally a yellowish orange color. You just point to it – there it is, up in the sky, the Sun.

However, many things can block the Sun. Usually, it is clouds that block the Sun, but not always. Let’s take a tour of the astonishing number of things that can block the Sun.

Click here to continue reading…

Animal constellations in the night sky. How many are there?

There are 42 animal constellations in the night sky.

That is almost half of the official 88 constellations!

Here are the other types of constellations you will find in the celestial sphere. This is a fun activity for kids astronomy!

There are 42 animal constellations, 28 objects, 14 humans, 2 chimeras (a mix of human and animal), and 2 natural features (a river and a mesa).

Constellations are of many types. There are 42 animal constellations, 28 objects, 14 human constellations, 2 chimeras, and 2 natural features
88 official constellations broken down into 5 groups: 42 animals, 28 objects, 14 humans, 2 chimeras, and 2 natural features.

The 88 constellations listed by type:Click here to continue reading…

Blue Moon, Dark Moon, Nose Moon, Tail Moon

What is a Blue Moon?

The year 2018 is a Blue Moon bonanza! There was one in January and one on March 31st. The next one won’t arrive until October 2020. But, don’t worry… we’ve got 3 other types of moons lined up for you.

A blue moon tinted blue to make it look like the moon is actually blue. A blue moon means 2 full moons in a calendar month.
A Blue Moon. (This image was tinted to make it blue. No, a Blue Moon is not blue.)

The Basics

A Blue Moon happens when there is a Full Moon on the 1st* day of the month and a Full Moon on the last* day of the month. Two full moons in one month!

In other words, a Blue Moon is when there is a full moon twice in the same month. These two full moons always happen on the 1st or 2nd and the 30th and 31st of a month. “Blue Moon” is just a name for the second moon in that month – the moon does not turn the color blue.

Read on to learn about how the Blue Moon came to be and some suggestions for giving the other moon phases “Blue Moon” style names when they appear twice in a month. Suggestions are: Dark Moon, Nose Moon, and Tail Moon.Click here to continue reading…

Quiz – Can we see the Sun at midnight? Where is the Sun?

Can we see the Sun at midnight?

Yes. We can see the Sun at midnight. But, only if we are at one of the polar regions during the Summer season.

A quiz – seeing the Sun at midnight – don’t scroll til you try to answer!

When you see the Sun “rising” in the morning at dawn you are facing the east.

When you see the Sun “setting” at the end of the day you are facing the west.

Assuming you are not above the Arctic circle and not too close to the equator… if you could look right at the Sun (when the night is exactly half over) – by looking through the Earth – which cardinal direction would you be facing? East, West, North, or South?

Looking north or south to see the Sun at midnight?
A compass rose showing the cardinal directions.

Click here to continue reading…

“Star In a Star” Translated into 90 languages

Translation of Star In A Star Physical Astronomy articles

Star In A Star logo transparent view of Kepler's Great Stellated Dodecahedron to create a star in a star view
Would you like to learn how to say the word “star” in languages that are not your own? All of the articles about Physical Astronomy here at Star In A Star can be automatically translated. This amazing Google Translate widget lets you choose any language.

Google translate widget providing translation of Physical Astronomy teaching material to a global language audience
Google Translate widget can be used to translate these articles into any language.

Try it out! If you are on desktop … click the link at the top right to translate. If you are on mobile, click the translate widget at the bottom of the page.
For a bit of fun today… Here is a list of languages and the phrase “Star In A Star” in that language. I particularly like the languages where the word “star” changes slightly if it is inside another star (in Bosnian: zvezda u zvezdu). Also, I am fond of non-roman script languages – just for how beautiful they look ( this is Lao: ດາວໃນດາວ ).
Afrikaans: ster in ‘n ster
Arabic: نجمة في نجم
Azerbaijani: bir ulduzda ulduz
Belarusian: зорка ў зорцы
Bulgarian: звезда в звезда
Bengali: একটি তারকা তারকা
Bosnian: zvezda u zvezdu
Catalan: estrella en una estrella
Cebuano: bituon sa usa ka bituon
Czech: hvězdička ve hvězdě
Welsh: seren mewn seren
Danish: stjerne i en stjerne
German: star in a star
Greek: αστέρι σε ένα αστέρι
English: star in a star
Esperanto: star in a star
Spanish: estrella en una estrella
Estonian: star täht
Basque: izar bat izar batean
Persian: ستاره در یک ستاره
Finnish: tähti tähteä
French: étoile dans une étoile
Irish: réalta i réalta
Galician: estrela nunha estrela
Gujarati: સ્ટારમાં તારો
Hausa: star a star
Hindi: स्टार में स्टार
Hmong: star in a star
Croatian: zvijezda u zvijezdi
Haitian Creole: zetwal nan yon etwal
Hungarian: csillag egy csillagban
Armenian: աստղ աստղում
Indonesian: bintang di sebuah bintang
Igbo: kpakpando na kpakpando
Icelandic: stjörnu í stjörnu
Italian: stella in una stella
Hebrew: כוכב בכוכב
Japanese: 星の星
Javanese: bintang ing sawijining bintang
Georgian: ვარსკვლავი ვარსკვლავი
Kazakh: жұлдызға жұлдыз
Khmer: តារាក្នុងផ្កាយ
Kannada: ನಕ್ಷತ್ರದಲ್ಲಿನ ನಕ್ಷತ್ರ
Korean: 스타의 스타
Latin: star in a star
Lao: ດາວໃນດາວ
Lithuanian: žvaigždė žvaigždė
Latvian: zvaigzne zvaigznīte
Malagasy: kintana amina kintana
Maori: whetu i roto i te whetu
Macedonian: ѕвезда во ѕвезда
Malayalam: ഒരു നക്ഷത്രത്തിൽ നക്ഷത്രം
Mongolian: одтой од
Marathi: तारा तारा
Malay: bintang dalam bintang
Maltese: star fi stilla
Myanmar (Burmese): ကြယ်အတွက်ကြယ်ပွင့်
Nepali: स्टारमा तारा
Dutch: ster in een ster
Norwegian: stjerne i en stjerne
Chichewa: nyenyezi mu nyenyezi
Punjabi: ਸਟਾਰ ਵਿਚ ਸਟਾਰ
Polish: gwiazda w gwiazdce
Portuguese: estrela em uma estrela
Romanian: stea într-o stea
Russian: звезда в звезде
Sinhala: තරුවක තරුවක
Slovak: hviezdička v hviezde
Slovenian: zvezda v zvezdi
Somali: xiddigta xiddig
Albanian: yll në një yll
Serbian: звезда у звезду
Sesotho: naleli linaleli
Sundanese: béntang di béntang anu
Swedish: stjärnan i en stjärna
Swahili: nyota katika nyota
Tamil: நட்சத்திரத்தில் நட்சத்திரம்
Telugu: స్టార్ లో స్టార్
Tajik: ситораи дар ситора
Thai: ดาวในดาว
Filipino: bituin sa isang bituin
Turkish: bir yıldızla yıldız
Ukrainian: зірка у зірки
Urdu: ایک ستارہ میں ستارہ
Uzbek: yulduzli yulduz
Vietnamese: sao trong một ngôi sao
Yiddish: שטערן אין אַ שטערן
Yoruba: Star ni irawọ kan
Chinese: 明星在一个明星
Chinese (Simplified): 明星在一个明星
Chinese (Traditional): 明星在一個明星
Zulu: inkanyezi kwenkanyezi

Physical Astronomy – Definition of a New Way of Teaching

Definition of Physical Astronomy

Physical astronomy definition using Leonardo DaVinci's Vitruvian Man drawing surrounded by moon phase images
Vitruvian Man with Moon Phases

Physical Astronomy is a new way of teaching astronomy that emphasizes the human body and its relationship to other moving objects in space. The goal is to bring geometric and scientific awareness to a child’s everyday sky observations. Kids learn easily visible sky motions at a “kid’s eye level.”

The Sun does not move… we move

One of the first steps in Physical Astronomy is to forget you ever heard the words “Sunset” or “Sunrise.”  These words (while rife with history, beautiful in their own right, and descriptive) are scientifically wrong. These words obscure the truth of our trip around the Sun. We are on the Earth, the Earth is spinning; the Sun appears to be moving, but it is us moving. Click here to continue reading…

Galaxy Rise

Physical Astronomy by Daniel Cummings

A still more glorious dawn awaits Not a sunrise, but a galaxy rise A morning filled with 400 billion suns The rising of the milky way.

The Sun rises. The Moon rises. Stars rise. The Galaxy rises – twice.

Each day the Earth rotates and sky objects (seem to) rise in the Eastern sky. The Sun, the Moon, the Stars, and the Galaxy rise at various times.

The Sun “rises” once-a-day at the start of the day.

The Moon “rises” once-a-day at different times of the day and night depending on the moon’s orbit around the Earth (its phase).

The Stars “rise” once-a-day – all night long, one after another and in groups.

The Milky Way Galaxy “rises” twice a day – once on its bright (center) side and then 12 hours later on its dim (outer arm) side.

We can orient our bodies to the rising of the Milky Way. And we can experience our daily movement as “plunging through” this flat disk of stars.

Click here to continue reading…

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