Bá¹›hat samhita- chapter 35 (6th century CE) describes formation of rainbow. This was later proposed by Sir Issac Newton nearly after 11 centuries. The verse is as follow.
सूर्यस्य विवधवर्णाः पवनेन
विघट्टिताः कराः साभ्रे ।
वियति धनुः संस्थानाः
ये दृश्यन्ते तदिन्द्रधनुः ।।
Meaning: The multi colored rays of the Sun, being dispersed in a cloudy sky, are seen in the form of a bow, which is called the rainbow.
Even in Vedas 7 colors of light is represented by 7 horses of God Sun which was shown much later. In fact, the same scripture describes formation of thunderbolt as well.




Traditions in Hinduism were considered mainly as superstitions, but with the advent of science, it is becoming evident that these traditions are based on some scientific knowledge and moved from generations to generations as traditions. Though the common people did not know science in it, they were following it very faithfully over the years. This article is an attempt to bring forward the science involved in these traditions and rituals. Ancient Rishis, which were scientists actually, did not tell the common people the science involved in these traditions but instead related them with the God and religion, so that the common people would benefit from them.

1. Concept of Gravity:

Vaishesika Sutras discuss about Gravity which I discuss in my answer here.Relevant quotes from that answer are:
आत्मकर्म हस्तसंयोगाश्च । संयोगभावे गुरुत्वात्पतनम।
नोदनाद्यभिषोः कर्म तत्कर्मकारिताच्च संस्कारादुत्तरं तथोत्तरमुत्तरं च । संस्काराभावे गुरुत्वात्पतनम।
अपां संयोगाभावे गुरुत्वात्पतनम। द्रवथ्वास्यन्दनम् ।
Action of body and it's members is also from conjunction with the hand.In the absence of conjunction falling results from Gravity. The first action of arrow is from impulse; the next is resultant energy produced by the first action, and similarly the next next. In the absence of resultant/propulsive energy generated by action, falling results from Gravity. The falling of water in absence of conjunction is due to Gravity. Flowing results from fludity.
2. Concept of Time Dilation:
We can find various stories about Time Dilation in Hindu scripture. The most famous is the story of Kakudami which Idiscuss here. They  sit in BrahmaLoka for only about 20 minutes and millions if years passes in the Earth. Relevant verses from Srimad Bhagvatam 9.3 is as:
आवर्तमाने गान्धर्व स्थितो ’लब्ध-क्षणः क्षणम् ।
तद्-अन्त आद्यम् आनम्य स्वाभिप्रायं न्यवेदयत्।।
तच् छ्रुत्वा भगवान् ब्रह्मा प्रहस्य तम् उवाच ह।
अहो राजन् निरुद्धास् ते कालेन हृदि ये कृताः।।
तत् पुत्र-पौत्र-नप्तॄणां गोत्राणि च न शृण्महे।
कालो ’भियातस् त्रि-णव-चतुर्-युग-विकल्पितः।।

When Kakudmi arrived there, Lord Brahma was engaged in hearing musical performances by the Gandharvas and had not a moment to talk with him. Therefore Kakudmi waited, and at the end of the musical performances he offered his obeisances to Lord Brahma and thus submitted his long-standing desire. After hearing his words, Lord Brahma, who is most powerful, laughed loudly and said to Kakudmi: O King, all those whom you may have decided within the core of your heart to accept as your son-in-law have passed away in the course of time. Twenty-seven catur-yugas have already passed. Those upon whom you may have decided are now gone, and so are their sons, grandsons and other descendants. You cannot even hear about their names.

Concept of Multiverses:

The concept of Multiverse has not been practically proved by modern science. But still it is an interesting concept in Modern science also. Hindu scriptures talk about multiverses. For instance as I discuss in my answer here, Srimad Bhagvatam in10.14.11 talks of multiverses:
क्वाहं तमो-महद्-अहं-ख-चराग्नि-वार्-भू-
 संवेष्टिताण्ड-घट-सप्त-वितस्ति-कायः ।
क्वेदृग्-विधाविगणिताण्ड-पराणु-चर्या-
 वाताध्व-रोम-विवरस्य च ते महित्वम् ।।

What am I, a small creature measuring seven spans of my own hand? I am enclosed in a potlike universe composed of material nature, the total material energy, false ego, ether, air, water and earth. And what is Your glory? Unlimited universes pass through the pores of Your body just as particles of dust pass through the openings of a screened window.
Similarly as discussed in answer hereDevi Bhagvatam also states presence of other Brahma, Vishnu and Rudras in other universes:
Then the car, where we were situated, began to get up high in the sky, and in the twinkling of an eye, we reached Brahmâ loka, that is saluted by all the Devas. There S'ambhu and Kes'ava were greatly bewildered to see Brahmâ of that place. In the council hall of Brahmâ, the Vedas with their Angas, the serpents, hills, oceans and rivers were seen. Seeing all these, Visnu and Mahes'vara asked me :-- “O Four-faced one! Who is this eternal Brahmâ? I replied :-- I do not know who is this Brahmâ? Who am I? and who is He? why has this error come over me? You, too, also are gods so you can better ponder over it.”
Similarly as quoted in the same answer, chapter 10 'Shiva swallowing poison' of Skandha Purana also states:
He (Ganesha) saw crores of spherical Cosmic Eggs like so many atoms.They were getting merged and dissolved in Mahesha who was in linga form.
Similarly as I discuss in my answer hereRamcharitmanas also mentions Kakabhusundi visiting multiple universes and even visiting himself:
In all these universes I saw myself in every universe. Each universe had its own Ayodhya with its own Sarayµu and its own men and women. And listen, dear Garuda : Ramas parents Dasaratha and Kausalya as well as Ramas brothers, Bharata and others, were all different in each universe. In each such universe I witnessed the descent of Rama as well as the infinite variety of His childish sports.

Concept of Universe as being Projection in space-time:

As I discuss in my answer here Vedas state Universe as being appearance in space time.
पूर्ण कुम्भोदिः काल आहितस्तं वै पश्यामो बहुदा नु सन्तः । [AtharvaVeda 19.53.3]

A full pot has been placed in Time and it is that which we see manifoldly.
Also, in the Dakshinamurty stotram composed by Adi Shankara he states:
बीजस्याऽन्तरिवाङ्कुरो जगदिदं प्राङ्गनिर्विकल्पं पुनः
मायाकल्पितदेशकालकलना वैचित्र्यचित्रीकृतम् ।

This World is Like a Sprout of a Seed Within which transforms what is Changeless state Before, appear Again as Space and Time, and endless Varieties of Pictures over it; all due to the Creation of Maya.

6) Concept of Cyclic Nature of Time:

As I discuss in my answer here Rig Veda states about Cyclical Nature of Time and Creation:
सूरय्याचन्द्रमसौ धाता यथा पूर्वमकल्पयत् I
दिवं च पृथ्वीं  च अंतरिक्षमथो स्वः   II  RigVeda 10.190.3  II

"The Ordainer created the sun and moon like those of previous cycles.He formed in order Heaven and Earth, the regions of the air, and light."

 The above I have quoted are some verses/stories which can be related to modern scientific discoveries. There are still much more things which I have to write here I will try to continue updating the answer regularly.