Convert wavelength in petametres to wavelength in metres [m] Online | Free frequency-wavelength Converter

The Scale of Interstellar and Cosmological Waves

A petametre (Pm) equals 1,000 terametres (10¹⁵ metres), representing unimaginably vast distances that describe the longest electromagnetic wavelengths in the universe. These wavelengths correspond to frequencies in the attohertz (10⁻¹⁸ Hz) and lower ranges, which are mostly relevant in cosmology, astrophysics, and the study of gravitational waves and large-scale cosmic phenomena.

For context, a frequency of 1 attohertz (10⁻¹⁸ Hz) corresponds to a wavelength of approximately 300 petametres. This scale is far beyond any human-made signals and reflects waves that stretch across entire galaxies or even clusters of galaxies. Such waves help scientists study the cosmic microwave background (CMB) fluctuations, the large-scale structure of the universe, and primordial gravitational waves created shortly after the Big Bang.

Using petametres to measure wavelength allows researchers to grasp the vastness of these cosmic oscillations and the slowest processes influencing the universe’s evolution. These extreme wavelengths provide crucial insight into the origins, expansion, and ultimate fate of the cosmos.

Measuring Long Electromagnetic Waves

The metre (m) is the standard SI unit of length and is widely used to express longer wavelengths of electromagnetic radiation, particularly in the radio wave portion of the spectrum. Wavelengths in the metre range correspond to frequencies from about 3 MHz to 300 MHz, covering parts of the VHF (Very High Frequency) and HF (High Frequency) bands. Common applications include AM and FM radio broadcasting, marine and aviation communication, shortwave radio, and amateur (ham) radio.

For example, an AM radio station transmitting at 1 MHz has a wavelength of 300 metres, while FM radio at 100 MHz corresponds to a 3-metre wavelength. These long wavelengths can travel great distances, diffract around obstacles, and reflect off the ionosphere, making them ideal for long-range communication.

Using metres to describe wavelength is particularly helpful in large-scale systems like radio towers and antennas, where antenna size often relates directly to a fraction of the wavelength. Understanding wavelengths in metres allows engineers and technicians to design effective communication systems, optimize signal coverage, and analyze wave behavior over long distances.