I have written articles on the weapons , including WMD, used in ancient India.
There were two types.
Sastra , the physical weapons, like Sword,Mace, Arrows.. and
Astra, the ones that carry weapons of Mass Destruction on the one hand and another devastating the enemy and his land with specific calamity Like Fire, Rain, Storms and psychological variety like Mohanastra which renders people unconscious, and Sammohanatsra which leaves one confused.
Three Astras are most potent.
And there is a very rare Brahmasiroastra.
Please read may articles on each.
I have also provided a detailed list of Astras and the Invocation Mantra for Brahmastra.
Brahmastra is believed to be an Atom Bomb and Brahma Sirastra a Neutron Bomb,
About ancient atomic explosions Oppenheimer stated that “In ancient India, we find words for certain measurements of length, one was the distance of light-years and one was the length of the atom. Only a society that possessed nuclear energy would have the need for such words.”..
Historian Kisai Mohan Ganguli says that Indian sacred writings are full of such descriptions which sound like an atomic blast as experienced in Hiroshima and Nagasaki. He says references mention fighting sky chariots and final weapons. An ancient battle is described in the Drona Parva, a section of Mahabharata. “The passage tells of combat where explosions of final weapons decimate entire armies, causing crowds of warriors with steeds and elephants and weapons to be carried away as if they were dry leaves of trees,” says Ganguli.
Consider these verses from the ancient epic Mahabharata,
““A single projectile charged with all the power of the universe. An incandescent column of smoke and flame as bright as the thousand suns rose in its entire splendor. A perpendicular explosion with its billowing smoke clouds. The cloud of smoke rising after its explosion formed into expanding round circles like the opening of giant parasols. It was unknown weapon, an ironic thunderbolt, A gigantic messenger of death, which reduced to ashes.
The Devastating Power of a Nuclear Bomb.
Entire race of the Virshins and the Andhakas were destroyed. The corpses were so burned as to be unrecognizable. The hair and nails fell out, pottery broke without apparent cause,And the birds turned white. After a few hours all foodstuffs were infected. To escape from this fire the soldiers threw themselves in streams to wash themselves and their equipment.” Until the bombing of Hiroshima and Nagasaki, modern mankind could not imagine any weapon as horrible and devastating as those described in ancient Indian texts. Yet they very accurately described the effects of atomic explosion which is not possible unless they have experienced a similar one those days. Radioactive poisoning will make hair and nails fall out. Immersing oneself in water gives some respite, though it is not a cure.’
How is Bramastra was Designed.
There are some verses that depict the nature of these astra-s. A few of them are given under. Though we may not actually acquire a projectile power with these verses, they may at least detail what these missiles are. The source of these verses is untraceable, but they are said to be in puraaNaa-s, and Shiva informs Sage Narada, about the missiles as below:
vaantam vahni samaayuktam vyomahaalaa samanvitam |
meSha dvayam danta yutam haalaahalam ataH param |
ghana aadyam vaayu puurvam ca danta yuktam athaanvitam |
saram R^ikSha poaryaayam bhaantam bhR^igu mataH param ||
ambaram vaayu sa~NyuktaH ari mardanam apyutaH |
pradiiptam atha avaktavyam paramam ca padam tataH |
tat ete pade prayoktavye gaayatryaa madhyamam tataH |
pada trayam prayoktavyam etat brahma astram iiritam ||
“It contains air, fire and cosmic poison, two goat-like fangs, full of poison, weighty, emits air, contains mercury, fiery, sparkling, sky is filled with air, enemy-killing, greatly radiant and it is projected with three hymns, Gayatri at its centre, it is known as brahma-astra’
Citation and source for sloka for Bala Kanda Of Valmiki Ramayana Sarga 27 foot note
Image Credits for Image I and ancient weapons with Invocation Mantra Aksharas.