Learn Hardcore Norwegian: Om natten ser vi på månen og tenker på alle planetene i universet. - At night we look at the moon and think about all the planets in the universe.

The preposition om is very flexible in Norwegian. In time expressions like om natten, it usually means “in/at/during” and refers to a general or habitual time.

So:

om natten = at night / during the night (in general)
om morgenen = in the morning
om sommeren = in (the) summer

The sentence is talking about what we (typically / often) do at night in general, not on one specific night, so om natten is the natural choice and is best translated as at night or during the night in English.

What is the difference between om natten, om natta, på natten, and i natt?

They are all related but not identical:

om natten
- Standard Bokmål, slightly more formal/neutral.
- Means at night / during the night in general or habitually.
om natta
- Also standard Bokmål (using the feminine form of natt).
- Sounds more colloquial/everyday.
- Meaning is the same as om natten.
på natten / på natta
- Also used, often regionally or colloquially.
- Often interchangeable with om natten / om natta.
- Some speakers feel om natten is a bit more “textbook”, på natta more spoken.
i natt
- Refers to a specific night, usually the night that has just passed or the upcoming night.
- Example: I natt sov jeg dårlig. = Last night I slept badly.

In your sentence, we are talking about a habitual action, so om natten / om natta fits best.

Why is it Om natten ser vi... and not Om natten vi ser...?

Norwegian main clauses follow the V2 rule (Verb-second):

The finite verb (here: ser) must be the second element in the sentence.

When you start the sentence with an adverbial like om natten (“at night”), that counts as the first element. The finite verb must then come next:

Om natten (1st element) ser (2nd element) vi på månen...

If you said Om natten vi ser..., the verb would be in third position (om natten = 1st, vi = 2nd, ser = 3rd), which breaks the V2 rule and sounds ungrammatical.

You could also say:

Vi ser på månen om natten.

Here, vi is first, ser is second, so it also follows the V2 rule.

Why do we say ser på månen instead of just ser månen?

Norwegian distinguishes between:

å se noe = to see something (perceive it with your eyes, possibly unintentionally)
å se på noe = to look at / watch something (actively direct your gaze)

In your sentence, the meaning is that we look at the moon, not just that we (happen to) see it. So you need på:

ser på månen = look at the moon / watch the moon
ser månen = see the moon (it’s visible to us)

Similar patterns:

se på TV = watch TV
se på stjernene = look at the stars

Why is it månen and not en måne or just måne?

Norwegian has definite and indefinite forms built into the noun, using an ending:

en måne = a moon (indefinite singular)
månen = the moon (definite singular)

Here we mean the moon – the one that orbits Earth, a specific, unique thing. In that case, Norwegian uses the definite form:

på månen = at/on the moon / the moon

If you said en måne, it would sound like “a moon” in the sense of one of many moons (for example, moons of different planets), which is not what we mean here.

Why do we say alle planetene instead of alle planeter?

Both are possible Norwegian phrases, but they do not mean exactly the same:

alle planetene
- Definite plural: “all the planets”
- Refers to a specific, complete set of planets (here: all the planets that exist in the universe).
alle planeter
- Indefinite plural: “all planets” (more like “every planet, any planet”)
- Feels more general/abstract and doesn’t point to one clearly defined group.

In your sentence:

alle planetene i universet = all the planets in the universe (the full set of them)

Using i universet already defines which planets we’re talking about, so the definite form planetene is natural.

Why does månen end in -en, but planetene ends in -ene?

Because they have different number (singular vs plural) and both are in the definite form:

månen
- From en måne (indefinite singular)
- månen = definite singular (“the moon”)
- Ending: -en
planetene
- From en planet (indefinite singular)
- Plural indefinite: planeter (“planets”)
- Definite plural: planetene (“the planets”)
- Ending: -ene

So:

-en → definite singular for masculine nouns
-ene → definite plural for many noun types

That’s why you see månen (one specific moon) and planetene (all of the planets).

Why is it tenker på and not tenker om?

In this context, tenke på noe is the normal phrase for “to think about something” in the sense of having it in your mind, imagining it, daydreaming about it:

Vi tenker på alle planetene i universet.
= We think about all the planets in the universe (they occupy our thoughts).

tenke om is much less common and usually appears in fixed expressions like:

Hva tenker du om dette? = What do you think about this? (opinion)
Even there, many Norwegians would also say Hva synes du om dette?

So:

tenke på = have something in your thoughts / mentally focus on it
tenke om = mostly used when asking for an opinion, often replaced by synes om

In your sentence we are not giving an opinion; we’re mentally picturing the planets, so tenker på is correct.

Why do we say i universet and not på universet?

Norwegian typically uses:

i for being in/inside something or within a space/area
på for on surfaces, on top of something, or in some abstract fixed expressions

The universe is conceptualized as a space we are inside of, so i universet (“in the universe”) is natural:

i universet = in the universe
på universet would sound wrong in standard Norwegian.

Compare:

i verden = in the world
i byen = in the city
på bordet = on the table

Can I move om natten to the end and say: Vi ser på månen og tenker på alle planetene i universet om natten?

Yes, that word order is grammatical and natural:

Om natten ser vi på månen og tenker på alle planetene i universet.
Vi ser på månen og tenker på alle planetene i universet om natten.

Both mean the same thing.

Differences in feel:

Om natten at the beginning:
- Emphasizes the time frame: As for at night… this is what we do.
om natten at the end:
- Feels a bit more neutral, almost like an afterthought: …in the universe, at night.

But in everyday speech, the difference is small; both are very acceptable.

What are the grammatical genders and basic forms of the nouns in this sentence?

Here are the main nouns with their genders and forms (Bokmål):

natt (night)
- Gender: feminine or masculine (both are allowed in Bokmål)
- Indefinite singular: ei natt / en natt
- Definite singular: natta / natten
- Indefinite plural: netter
- Definite plural: nettene
- In the sentence: om natten (definite singular, masculine form)
måne (moon)
- Gender: masculine
- Indefinite singular: en måne
- Definite singular: månen
- Indefinite plural: måner
- Definite plural: månene
- In the sentence: månen (definite singular)
planet (planet)
- Gender: masculine
- Indefinite singular: en planet
- Definite singular: planeten
- Indefinite plural: planeter
- Definite plural: planetene
- In the sentence: planetene (definite plural)
univers (universe)
- Gender: neuter
- Indefinite singular: et univers
- Definite singular: universet
- (Rarely used in plural)
- In the sentence: universet (definite singular)

What tense are ser and tenker, and what are their infinitive forms?

Both ser and tenker are in the present tense.

Infinitives:

å se = to see / to look (depending on context; with på it means to look at)
- Present: ser
- Example: Vi ser på månen.
å tenke = to think
- Present: tenker
- Example: Vi tenker på alle planetene.

Norwegian uses the present tense for:

actions happening now, and
habitual/general actions (like English simple present).

Here it’s the second use: it describes what we generally do at night.

How is the sentence pronounced, and are there any tricky sounds for English speakers?

Approximate pronunciation (using English-like hints):

Om natten ser vi på månen og tenker på alle planetene i universet.
→ om NAT-ten ser vee paw MÅ-nen oo TEN-ker paw AL-le PLA-ne-te-ne ee oo-NEE-ver-set

Some points:

om – short o, like British not.
natten – tt is a clear [t]; final -en often reduced, sounding like “nattn”.
ser – like English “sair” (similar to “hair” but with s).
vi – v
- i like English “vee”.
på – long vowel, somewhere between “paw” and “po”, with lips rounded.
månen – å like in “law”; -en again often reduced.
tenker – kj-sound in some dialects for k before e, but in many Bokmål-speaker accents it’s simply [ten-ker].
alle – roughly “AL-leh”.
planetene – stress on pla-NE-te-ne (secondary on NE).
i – like English “ee”.
universet – stress on ver: oo-nee-VER-set; final -et often like -e (“versse”).

Regional accents vary, but these hints are close enough for a learner to be understood.