Learn Hardcore Indonesian: Di museum sains, kami belajar tentang roket dan galaksi. - At the science museum, we learn about rockets and galaxies.

Emphasizes the location: At the science museum (that’s the important part), we learned about rockets and galaxies.
Is very natural in Indonesian, especially in written or more formal language.

Putting it at the end:

Feels a bit more neutral in emphasis.
Is also perfectly natural.

So word order is flexible here; you just cannot break di + place apart. The whole phrase di museum sains has to stay together as a unit.

What’s the function of di in di museum sains? How is it different from ke or pada?

di is a preposition that usually means “at / in / on” (a location where something is).

di museum sains = at the science museum / in the science museum

Compare:

ke = to (a place), indicates movement towards somewhere
- Kami pergi ke museum sains. = We went to the science museum.
di = at / in (a place), indicates being in a location
- Kami belajar di museum sains. = We studied at the science museum.
pada is more formal and often used with time or sometimes with people/abstract nouns:
- pada hari Senin = on Monday
- pada guru kami = to our teacher (formal)

So in this sentence, di is correct because it describes the place where you did the learning, not the movement to that place.

Why is there a comma after Di museum sains? Is it required?

The comma after Di museum sains is stylistic but very common.

You often use a comma when a sentence starts with an adverbial phrase (time, place, manner):

Di museum sains, kami belajar…
Kemarin, saya pergi ke pasar. = Yesterday, I went to the market.
Di rumah, dia biasanya membaca. = At home, he usually reads.

In everyday informal writing (texts, chats), people often skip the comma:

Di museum sains kami belajar tentang roket dan galaksi.

So:

With comma: more formal/standard, recommended in writing.
Without comma: still understandable and not “wrong” in casual contexts.

What is the difference between kami and kita, and why is kami used here?

Both kami and kita mean “we / us”, but they differ in who is included:

kami = we (NOT including the person you’re talking to)
- Used when “we” = speaker + someone else, but not the listener.
kita = we (INCLUDING the person you’re talking to)
- Used when “we” = speaker + listener (and maybe others).

In this sentence:

kami belajar tentang roket dan galaksi
implies: we (but not you, the listener) learned about rockets and galaxies.

If the speaker wants to include the listener (e.g., a teacher talking to their class about what they did together), they might say:

Di museum sains, kita belajar tentang roket dan galaksi.
= At the science museum, we (you and I) learned about rockets and galaxies.

So kami is used when the listener was not part of the group that went to the museum.

Why do we say belajar tentang? Could you just say belajar roket dan galaksi?

In Indonesian, belajar (“to study / to learn”) often appears with tentang (“about”) when you specify a topic:

belajar tentang roket dan galaksi = learn about rockets and galaxies

You can sometimes drop tentang, especially in short, informal contexts when it’s clear:

Saya belajar matematika. = I study math.
Dia belajar musik. = He/She studies music.

But with more “content-like” topics (things you learn about rather than a school subject), tentang is more natural:

belajar tentang roket
belajar tentang sejarah Indonesia
belajar tentang budaya Jepang

So:

belajar matematika (OK, treated as a subject)
belajar tentang roket dan galaksi sounds more complete and natural than just belajar roket dan galaksi.

Why aren’t roket and galaksi made plural? In English, we say “rockets and galaxies”.

Indonesian usually does not mark plural with a special ending like English -s.
One word form can mean singular or plural, depending on context:

roket = rocket / rockets
galaksi = galaxy / galaxies

In this sentence:

roket dan galaksi easily covers “rockets and galaxies” because the topic is general.

If you really need to emphasize plural, there are a few options:

Reduplication (repeating the noun) – common and natural:
- roket-roket = rockets
- galaksi-galaksi = galaxies
Using a number or quantity word:
- banyak roket = many rockets
- beberapa galaksi = several galaxies

But for general topics like in this sentence, roket dan galaksi is perfectly normal.

Are roket, galaksi, and sains Indonesian words or just borrowed from English?

They are loanwords, mostly from Western languages (often via Dutch/English), but they are fully accepted as standard Indonesian:

roket ← rocket
galaksi ← galaxy
sains ← science

They follow Indonesian spelling and pronunciation conventions.
Typical Indonesian pronunciations:

roket ≈ RO-ket (short e, like in “bed”)
galaksi ≈ ga-LAK-si
sains ≈ SA-ins (two syllables: sa
- ins), not exactly like English science.

Indonesian also has a more “pure” term for science: ilmu pengetahuan, but sains is very commonly used in contexts like museum sains, majalah sains (science magazine), etc.

There’s no word for “the” in museum sains. How do Indonesians say “the science museum” vs. “a science museum”?

Indonesian normally does not use articles like “the” or “a/an”.
So museum sains can mean:

the science museum
a science museum

The difference is understood from context, not from grammar.

If you really need to be specific, you can add other words:

museum sains itu = that science museum / the (aforementioned) science museum
sebuah museum sains = a science museum (one science museum)

But in most cases, simple museum sains is enough, and context tells the listener whether you mean “a” or “the”.

How do we know the sentence is past tense (“we learned”) when belajar doesn’t change form?

In Indonesian, verbs usually do not change form for tense. Belajar can mean:

learn / study (present)
learned / studied (past)
will learn / will study (future)

The tense is understood from context or from extra time words:

Kemarin kami belajar tentang roket.
= Yesterday we learned about rockets. (past)
Sekarang kami belajar tentang roket.
= Now we are learning about rockets. (present)
Besok kami akan belajar tentang roket.
= Tomorrow we will learn about rockets. (future; akan explicitly marks future)

In your sentence:

Di museum sains, kami belajar tentang roket dan galaksi.

If the surrounding context is a story about a past visit, English translates it as “we learned”, but the Indonesian word belajar itself does not show tense.

Does di here mean “in” or “at”? Is there a difference in Indonesian?

Indonesian di covers several English prepositions:

di can mean at, in, or sometimes on, depending on the noun that follows.

So:

di museum sains can be translated as either “at the science museum” or “in the science museum”.
Both are fine in English; Indonesian doesn’t distinguish here.

Other examples:

di rumah = at home / in the house
di sekolah = at school
di meja = on the table (depending on context; if you need to stress “on top of”, you might say di atas meja)

So English splits these ideas into different words (in / on / at), but Indonesian mainly uses di, and context fills in the nuance.