"Ile lat ma Wszechświat?"

Translation: How old is the Universe?

[Euhan1]

...and when is its birtday?

[MariahSome1]

Birthday

[rafaelblucena]

42!

[Mark958555]

Does Wszechświat need to be capitalized always?

[Jellei]

It doesn't, but in a way it's treated as a geographical name, same as names of stars, planets, or for example "Droga Mleczna" (Milky Way). Moreover, we only know one Universe, so it makes more sense to capitalize it.

[Mark958555]

While it's logical, I've never seen it capitalized in English. It's certainly not a big deal, though.

[AnthonyJ.Carlsen]

When you're asking about age for other things, like a cake or a baby, do you just change years to something more suitable, like days, months etc, or is there another way to ask how old something is?

[Emwue]

Indeed, you just change years to something else:

• „Ile dni ma [cośtam]” – '(lit.)How many days [something] has' – Could be asked for example about suspicious yoghurt you just found in your fridge
• „Ile miesięcy ma [cośtam]” – '(lit.)How many months […]' – Frequently used to inquire about the age of babies
• „Ile wieków ma [cośtam]” – '(lit.)How many centuries […]' – Age of trees, objects in museums and so on

[Erik787431]

Ma czternaście i pół miliarda lat!

[Ilya583989]

13.8 miliardów

[Jellei]

"13,8 miliarda", actually, every time when you have a fraction (8/10) the noun is singular Genitive, it works as "8/10 of a milliard/billion).