Hubble Space Telescope

History

The telescope is named after Edwin Hubble, the astronomer who proved the expansion of the Universe. The project began in the 1970s, and launch took place on April 24, 1990, aboard the Space Shuttle Discovery. The first images were blurry due to a mirror defect, but in 1993 astronauts installed corrective optics, and the telescope began working at full capacity.

How it works

Hubble uses a system of mirrors to focus light and digital sensors similar to camera matrices. It orbits Earth at about 27,000 km/h, completing a full orbit every 97 minutes. Solar panels power its instruments, and gyroscopes help it precisely point at targets, like a ship holding its course at sea.

History

The telescope is named after Edwin Hubble, the astronomer who proved the expansion of the Universe. The project began in the 1970s, and launch took place on April 24, 1990, aboard the Space Shuttle Discovery. The first images were blurry due to a mirror defect, but in 1993 astronauts installed corrective optics, and the telescope began working at full capacity.

How it works

Hubble uses a system of mirrors to focus light and digital sensors similar to camera matrices. It orbits Earth at about 27,000 km/h, completing a full orbit every 97 minutes. Solar panels power its instruments, and gyroscopes help it precisely point at targets, like a ship holding its course at sea.

History

The concept of a space telescope had been discussed since the 1940s, but full design began in the 1970s. Launch took place on April 24, 1990; spherical aberration of the primary mirror was soon discovered and corrected by servicing mission STS-61 in 1993. A total of five servicing missions were conducted (the last in 2009), upgrading instruments. The telescope is named after Edwin Hubble, whose work on redshift and Hubble's law laid the foundations of modern cosmology.

How it works

The Ritchey–Chrétien telescope collects light with a primary hyperbolic mirror and directs it to a secondary mirror, then to instruments. Stabilization is achieved with gyroscopes and magnetometers, precise pointing with guide star sensors. Scientific instruments include the Wide Field Camera 3, Cosmic Origins Spectrograph, and others. Data are transmitted via radio link through TDRS satellites. Hubble's law (v = H₀d) was empirically refined thanks to Hubble's observations of distant supernovae, leading to the discovery of accelerated expansion of the Universe. Gravitational lensing captured by the telescope has allowed mapping of dark matter in galaxy clusters. Transit spectroscopy of exoplanet atmospheres has revealed lines of water, methane, and other molecules.

Open problems & fun facts

The Hubble tension—discrepancy between measurements of the Hubble constant by different methods.; Detection of the first galaxies, which remained invisible to HST.; Direct observation of dark matter through gravitational lensing is limited by resolution.

💡 Hubble captured the famous Hubble Deep Field—a patch of sky the size of a grain of sand held at arm's length, revealing over 3000 galaxies. It also helped refine the age of the Universe—about 13.8 billion years.