Allah's Throne was on Water - Clarification

I hold the opinion that the water here refers to the space-time

36:40 It is not permitted to the Sun to catch up to the Moon, not can the night outstrip the day; Each swims along in orbit.

So we know that the Sun and the Moon are in the space. So when it's said that the Sun and the Moon swim, the space-time must be the water. If you look at the Einstein's space-time model, it closely resembles water. Space-time also has ripples or waves just like water.

And Allah knows best.

As muslims we must take it and believe wate(v)er is written in the holy book. Scrutinizing the word of Allah SWT is blasphemy.

No both the qur'an and sunnah actually emphasize only on the fact that water existed before the creation of the heavens and earth.

Al-Haafiz Ibn Hajar (may Allah have mercy on him) said: In the report of Ishaaq ibn Raahawayh it says “and the Throne is over the water.” The apparent meaning is that it was like that when the Prophet (blessings and peace of Allah be upon him) spoke these words. The apparent meaning of the hadeeth which comes before it is that the Throne was over the water before the creation of the heavens and earth, and the two hadeeth when taken together indicate that it is still over the water. End quote. Fath al-Baari, 20/496 (Source: islamqa #146779)

However ar-Rabi' ibn Anas has been quoted with the following interpretation -among many others- in Tafsir ibn Kathir -see here in Arabic-:
_{In the following I'm translating from Arabic, as these translations are of my own take them with the necessary care!}

وقال الربيع بن أنس : ( وكان عرشه على الماء ) فلما خلق السموات والأرض ، قسم ذلك الماء قسمين ، فجعل نصفا تحت العرش ، وهو البحر المسجور .
Ar-Rabi' ibn Anas said: (and His Throne had been upon water) and when HE created the heavens and earth. HE divided the water into two parts and made one half under the throne and this is the sea filled with fire

See also:

• And [by] the sea filled [with fire], (52:6)

Ar-Rabi' was again quoted in tafsir ibn Kathir of this verse say -see here in Arabic- :

قال الربيع بن أنس : هو الماء الذي تحت العرش ، الذي ينزل [ الله ] منه المطر الذي يحيي به الأجساد في قبورها يوم معادها . وقال الجمهور : هو هذا البحر .
Ar-Rabi' ibn Anas said: it is the water under the Throne from which Allah drops down the rain that gives life to the dead bodies in their graves at the hereafter. The majority says it is the sea we know.

• And when the seas are filled with flame (81:6)

A lot of the narrations seem to describe the water unlike the water we know for example inn Tafsir al-Qurtobi -see here in Arabic- you may read these two statements:

• قال كعب : خلق الله ياقوتة خضراء فنظر إليها بالهيبة فصارت ماء يرتعد من مخافة الله تعالى ; فلذلك يرتعد الماء إلى الآن وإن كان ساكنا ، ثم خلق الريح فجعل الماء على متنها ، ثم وضع العرش على الماء .
  Ka'ab (al-'Ahbaar) said: Allah created a green corundum then HE looked at it with prestige and it turned into water that trembles in fear of Allah the almighty. For this reason the water still trembles until now even if it was quiet. Afterwards HE created the wind and made the water on it, then HE placed the Thron on the water.

• وقال سعيد بن جبير عن ابن عباس : إنه سئل عن قوله - عز وجل - : وكان عرشه على الماء >>فقال : على أي شيء كان الماء ؟ قال : على متن الريح
  Sa'id ibn Jubair narrated from ibn 'Abbas that he was asked about the statement of Allah the almighty (and His Throne had been upon water) and on what was the water? And he replied it rode the wind.

So therefore it is a bit far fetched to say that it is the material from which Allah created the heavens and earth.