So Mahārāja Parīkṣit was so exalted king that by his invitation, the demigods would come and public could see. That was possible. That is stated here. He was so, I mean to say, exalted king, he could invite. And the kings also were invited. Just like Mahārāja Yudhiṣṭhira went. That was interplanetary exchange. That is now not... You cannot go by the sputniks to the heavenly planet. The moon planet is also one of the heavenly planet. Or the other planets. They are all heavenly planets. Ūrdhvam. Ūrdhvaṁ gacchanti sattva-sthāḥ (BG 14.18). When you are competent, fit, for going there, then you can go there. That is stated in the Bhagavad-gītā. Yānti deva-vratā devān pitṟn yānti pitṛ-vratāḥ, bhūtejyā yānti.. (BG 9.25). You can go, but you must be qualified, pitṛ-vratāḥ, deva-vratāḥ. Similarly, you can go to Kṛṣṇa also if you are kṛṣṇa-vratāḥ. Mad-yājino 'pi yānti mām. What to speak of going to other planets, if one is qualified, if one is pure devotee, Kṛṣṇa says, "He also comes to Me." So this exchange of going and coming is not difficult, provided a person is qualified. Not a cat and dog can go. That is not possible.
So another important point is... Ājahārāśva-medhāṁs trīn, three times. The aśvamedha-yajña is so expensive that the king of heaven, Indra, he executed the aśvamedha-yajña seven times. So Mahārāja Pṛthu was also going to complete seven times. So there was some, I mean to say, competition. The Indra would not allow him to complete seven times. Otherwise he would become equal with him. So amongst the kings, not only in this planet, but in other planets also, the aśvamedha-yajña was performed by very, very powerful rich kings, not ordinary kings. It is very expensive job. Because it is stated, bhūri-dakṣiṇān, and vast amount of money required for distribution in charity. Then you can perform aśvamedha-yajña. Similarly, there is gomedha-yajña. Aśvamedha-yajña was to send the horse with flag, that "Such and such king is the emperor of the whole world." So if some king in some state, he does not agree that "He is emperor," he will capture the horse, "I don't agree, I don't accept." Then there will be fight, "You have to accept." In this way there will be sacrifice.
So Mahārāja Parīkṣit was the emperor of the whole world, whole this planet. So he performed three times. Now, that means three times he challenged, "If there is any dispute, any objection of my becoming emperor?" This is aśvamedha-yajña. "If you have got any objection, then I will make you obliged to accept me. Otherwise, if you accept, that's all right. You remain in your state. Give me tax." This is the... So this is very expensive job. Formerly one king performed this aśvamedha-yajña, and bhūri-dakṣiṇān. He gave in dakṣiṇa... Dakṣiṇa means in charity. Just like you give dakṣiṇa to your spiritual master for initiation, similarly, here also, it is said, śāradvataṁ guruṁ kṛtvā. Everything must be executed under the guidance of a guru, not whimsically, "Oh, I have got my own idea, I have got my own God. I can do whatever I like." This is simply waste of time. Yaḥ śāstra-vidhim utsṛjya vartate kāma-kārataḥ (BG 16.23). In the Bhagavad-gītā it is said that "Anyone who does not follow the instruction of the śāstra, how things should be done," śāstra-vidhim utsṛjya vartate kāma-kārataḥ, "does things whimsically," na sukhaṁ sāvāpnoti, "he will never get happiness." Yaḥ śāstra-vidhim utsṛjya vartate kāma-kārataḥ, na sukhaṁ sa...
So everything should be done according to śāstra. And the śāstra should be guided by ācārya, guru. Ācārya means one who knows what is there in the śāstra. He practices in his life and teaches the disciple. He is called ācārya. Ācārya is not a whimsical thing. He must know. Therefore Parīkṣit Mahārāja appointed ācārya, śāradvatam. He is the brother of Droṇācārya. Droṇācārya was also ācārya, but he was military ācārya. And here he was ācārya for Vedic rituals, ācārya. Tad-vijñānārthaṁ sa gurum eva (MU 1.2.12). Guruṁ kṛtvā. In order to do things very rightly, you must appoint... Just like if you are going to the court to file some suit, do it very nicely. You have to appoint a very good lawyer. Similarly, these Vedic principles, the Vedic rituals, they should be performed under the direction of ācārya, guru, not whimsically. So therefore this kind of sacrifices are forbidden in this age, in this age.