Dirghatamas was one of the Angirasa Rishis, the oldest of the Rishi families, and regarded as brother to the Rishi Bharadvaja, who is the seer of the sixth Mandala of the Rig Veda. Dirghatamas is also the chief predecessor of the Gotama family of Rishis that includes Kakshivan, Gotama, Nodhas and Vamadeva (seer of the fourth Mandala of the Rig Veda), who along with Dirghatamas account for almost 150 of the 1000 hymns of the Rig Veda. His own verses occur frequently in many Vedic texts, a few even in the Upanishads.
He was the reputed purohit or chief priest of King Bharata (Aitareya Brahmana VIII.23), one of the earliest kings of the land, after whom India was named as Bharata (the traditional name of the country).
Bhishma tells the narrative of the birth of Dirghatamas in the Mahabharata (book1, Adi Parva, CIV): "There was in olden days a wise Rishi of the name of Utathya. He had a wife of the name Mamata whom he dearly loved. One day Utathya's younger brother Brihaspati, the priest of the celestials, endued with great energy, approached Mamata. The latter, however, told her husband's younger brother—that foremost of eloquent men—that she had conceived from her connection with his elder brother and that, therefore, he should not then seek for the consummation of his wishes. She continued, 'O illustrious Brihaspati, the child that I have conceived hath studied in his mother's womb the Vedas with the six Angas, Semen tuum frustra perdi non potest. How can then this womb of mine afford room for two children at a time? Therefore, it behoveth thee not to seek for the consummation of thy desire at such a time. Thus addressed by her, Brihaspati, though possessed of great wisdom, succeeded not in suppressing his desire. Quum auten jam cum illa coiturus esset, the child in the womb then addressed him and said, 'O father, cease from thy attempt. There is no space here for two. O illustrious one, the room is small. I have occupied it first. Semen tuum perdi non potest. It behoveth thee not to afflict me.' But Brihaspati without listening to what that child in the womb said, sought the embraces of Mamata possessing the most beautiful pair of eyes. Ille tamen Muni qui in venture erat punctum temporis quo humor vitalis jam emissum iret providens, viam per quam semen intrare posset pedibus obstruxit. Semen ita exhisum, excidit et in terram projectumest. And the illustrious Brihaspati, beholding this, became indignant, and reproached Utathya's child and cursed him, saying, 'Because thou hast spoken to me in the way thou hast at a time of pleasure that is sought after by all creatures,perpetual darkness shall overtake thee.' And from this curse of the illustrious Brishaspati Utathya's child who was equal unto Brihaspati in energy, was born blind and came to be called Dirghatamas (enveloped in perpetual darkness). And the wise Dirghatamas, possessed of a knowledge of the Vedas, though born blind, succeeded yet by virtue of his learning, in obtaining for a wife a young and handsome Brahmana maiden of the name of Pradweshi. And having married her, the illustrious Dirghatamas, for the expansion of Utathya's race, begat upon her several children with Gautama Dirghatamas as their eldest.
Asya Vamasya Hymn 
Dirghatamas is famous for his paradoxical apothegms. His mantras are enigmas: “He who knows the father below by what is above, and he who knows the father who is above by what is below is called the poet.”
The Asya Vamasya (RgVeda 1.164) is one of the sages most famous poems. Early scholars (such as Deussen in his Philosophy of the Upanisads) tried to say that the poems of Dirghatamas were of a later nature because of their content, but this has no linguistic support which has been argued by modern Sanskrit scholars (such as Dr. C. Kunhan Raja in his translation of the Asya Vamasya Hymn). The reason earlier western scholars believed it was of a later origin is because of the monist views found there. They believed that early Vedic religion was pantheistic and a monist view of god evolved later in the Upanisads- but the poems of Dirghtamas (1.164.46) which say "there is One Being (Ekam Sat) which is called by many names" proves this idea incorrect.
Earliest Mention of the Zodiac 
Some scholars have claimed that the Babylonians invented the zodiac of 360 degrees around 700 BCE, perhaps even earlier. Many claim that India received the knowledge of the zodiac from Babylonia or even later from Greece. However, as old as the Rig Veda, the oldest Vedic text, there are clear references to a chakra or wheel of 360 spokes placed in the sky. The number 360 and its related numbers like 12, 24, 36, 48, 60, 72, 108, 432 and 720 occur commonly in Vedic symbolism. It is in the hymns of the Rishi Dirghatamas (RV I.140 - 164) that we have the clearest such references.
Famous Sayings 
A number of famous sayings originate from the verses of Dirghatamas.
Another one bites the dust The first time the phrase “bites the dust” appears is in the Rgveda (1.158.4-5) where the poet Dirgatama has a prayer to the divine doctors and says ‘may the turning of the days not tire me, may the fires not burn me, may the wood-pyre not eat the earth, may the waters not swallow me’. There are disputes on what “bites the dirt” means in sayana’s commentary in the 14th century- which means the phrase had gone out of style in India at this time as most people began to be cremated instead of buried. But reading the padbandha, it's very clear that it refers to the wood-pyre eating earth, not the deceased human.
mā mām edho daśatayaś cito dhāk pra yad vām baddhas tmani khādati kśāṃ
Note the use of 3rd person singular verb ending -ti for khād (to eat). Dirghatama is using it as a prayer from death - such as don’t let me die and be burned. If it were a prayer saying "let me not eat the earth", the 1st person singular, -mi or -āni ("Verb conjugation in Vedic Sanskrit".) would have been used. Here, eating of earth effect is produced by charring of earth by burnt wood-pyre.
- Gupta, Nolini Kanta. “Seer Poets”, p.8
- Gupta, Nolini Kanta. “Seer Poets”. Sri Aurobindo Ashram, Pondicherry, 1970.
- Johnson, Williard. On the Rgvedai Riddle of the two birds in the Fig Tree (1.164.20-22) and the Discovery of the Vedic Speculative Symposium. American Oriental Society. 1976. http://www.jstor.org/pss/599827
- Mahabharata, book1, Adi Parva, CIV
- Rg veda, suktas 140 to 164
- Raja, Dr. C. Kunhan. Asya Vamasya Hymn, (printed 1956).
- Singh, Prof. satya Prakash. Life and Vison of the Vedic Seers 2: Dirghatamas. Standard Publishers, New Delhi, 2006.