The word antariksa in Vedas refers to space extensing outward from earth and time in Vedas is referred as Kaal. In many suktas of Vedic texts, duo of earth and sky referred as Dyāvā-Prthivī. It is called 'black' as it is dark. So let's discuss about what Vedic texts say about the SpaceTime.
Atharvaveda 19.53.3
पूर्ण कुम्भोऽधि काल आहितस्तं वै पश्यामो बहुधा नु सन्त Ι
स इमा विश्वा भुवनानि प्रत्यङ् कालं तमाहुः परमे व्योमन्ΙΙ
काल के ऊपर स्थित यह कुंभ ब्रह्मांड रूप से भरा हुआ हैΙ संत एवं ज्ञानीजन उस काल को अनेक रूपों में देखते हैंΙ प्राणियों के समक्ष प्रकट होने वाला काल उन्हें अपने में व्याप्त कर लेता हैΙ साधुजन उस काल को अनेक भेद से देखते हुए उसे आकाश के समान निर्लेप बनाते हैंΙ
Kala(काल) or Time is a like a full pot which never empties i.e. time is continous(Space-Time Continuum). Wise people see it in different ways. Kala is placed behind world(भुवनानि) and galaxies(विश्वा). We can't understand the real nature of time by looking towards Sun or any planet or any galaxy, Kala remains behind these celestial bodies and revolves around them. These celestial bodies are in space but Kala doesn't lie in space. Thus, sages say that Time is in super-space, beyond the space.
The reason why they call time is beyond space and it is in super-space is that the Big Bang Theory says that this Universe came into existence when one fireball exploded. If it is so,then even before explosion, there must be a few events (like formation of fireball). Thus, time must be present before space came into existence. Thus Vedic sages appears to be true. There is discussion in Rig Veda that nothing, no space, was present before the Universe came into existence.
The reason why they call time is beyond space and it is in super-space is that the Big Bang Theory says that this Universe came into existence when one fireball exploded. If it is so,then even before explosion, there must be a few events (like formation of fireball). Thus, time must be present before space came into existence. Thus Vedic sages appears to be true. There is discussion in Rig Veda that nothing, no space, was present before the Universe came into existence.