Due to the dominance of Vedanta school in present time, Sanatana Dharma (Hinduism) is often seen only in the light of Vedanta. If we go with respect to doctrines, Vedanta is only a small part of philosophies of Sanatana Dharma.

Sanatana Dharma is mainly represented by six philosophies like Vedanta, Mimamsa, Nyaya etc.. Among the six school of philosophy, Vaishesika is one of them. Vaisheshika philosophy was founded by Maharsi Kanada.

Just as Vedanta is represented by Brahma Sutra in a concise manner, Vaishesika philosophy is concised by Vaishesika Sutra. Vaishesika Sutra are very old texts. Even the western indologists date it to older than 500 BCE. And Vaisheshika Sutra clearly discuss about Gravity in the Sutras themselves.

Vaishesika Sutra discuss about role of Gravity in mainly three events:

1) Why does an object held fall when you let go?

To describe this first of all Sutra 5.1.6 states:

आत्मकर्म हस्तसंयोगाश्च ।

Action of body and it's members is also from conjunction with the hand.

As the above Sutra describes that it is due to conjunction with hand object remains. Then the next Sutra describes that in the absence of conjuction falling results due to Gravity.

संयोगभावे गुरुत्वात्पतनम (V.S. 5.1.7)

In the absence of conjunction falling results from Gravity.

Thus it clearly recognizes objects fall downward due to Gravity.

2) Why does an object thrown in air fall after sometime?

Then Vaishesika Sutra discuss role of Gravity in falling of moving objects. It gives through the analogy of arrow. First it gives mechanism of arrow projection in Sutra 5.1.17

नोदनाद्यभिषोः कर्म तत्कर्मकारिताच्च संस्कारादुत्तरं तथोत्तरमुत्तरं च ।।

The first action of arrow is from impulse; the next is resultant energy produced by the first action, and similarly the next next.

Then it explains why it falls in next Sutra.

संस्काराभावे गुरुत्वात्पतनम (V.S. 5.1.18)

In the absence of resultant/propulsive energy generated by action, falling results from Gravity.

3) Why does water fall (and rise) ?

Then the Sutras discuss cause of falling of water from sky.

अपां संयोगाभावे गुरुत्वात्पतनम (V.S. 5.2.3)

The falling of water in absence of conjunction is due to Gravity.

Then it discusses flow of water.

द्रवथ्वास्यन्दनम् (V.S. 5.2.4)

Flowing results from fludity.

Then it discusses why water rises.

नाड्यो वायुसंयोगादारोहणम् ।(V.S. 5.2.5)

The Suns rays (cause) the ascent of water through conjunction with air.

Thus from above Sutras, we can acknowledge that Vaisheshika Sutra clearly discuss Gravity. It uses the word "Gurutwa" which is also used in present time to represent Gravity. Gurutwa means force which arises due to mass.

However Vedanta School in Vedanta Sutra/ Brahma Sutra doesn't discuss about Gravity. In my view it is because it doesn't think Gravity is a worthy thing to be discussed as Vedanta Sutra are related to realization of Brahman and topics like Gravity aren't worthy to be discussed in Brahma Sutras.

One can read Vaisheshika Sutras with translation here.