sciencetech-blog

comments

We're used to seeing incredible satellite images of our planet, revealing everything from rocket fire to deforestation.

But back in the 1970s, these images looked more like faxed version of an atlas, revealing just how far the technology has come in just 40 years.

Now Nasa has released the first ever complete shot of the US, showing the contiguous 48 states, and stitched together from separate images in 1974.

Each of the 595 black and white image were taken at the same altitude of 560 miles (900km) and at the same angle. In 1974, the images were used by map makers, geologists and scientists to better understand changes in land formation

Considered to be state-of-the-art at the time, each of the 595 black and white image were taken at the same altitude of 560 miles (900km) and at the same angle

Overall, the map is 10 by 16 feet (3 metres by 5 metres), and the mosaic is produced at scale where one inch on the image equals a million inches on the ground.

In 1974, the images were used by map makers, geologists and scientists to better understand changes in land formation.

The were taken by the Earth Resources Technology satellite, or Landsat 1, which was launched on July 23, 1972 by a Delta 900 rocket from Vandenberg Air Force Base in California.

The US as seen by satellites today. The incredibly detailed satellite image can help reveal everything from deforestation to erosion

An image of the US in 2012 showing ''the glow of natural and human-built phenomena across the planet in greater detail than ever before'

Just two years after the construction of this, Landsat 1 discovered a tiny uninhabited island 12.4 miles (20km) off the eastern coast of Canada.

The satellite carried two wide-band video tape recorders that could store 30 minutes of scanner or camera data, giving it global coverage capability.

Today, Landsat 8 is orbiting Earth along with the Landsat 7 satellite in orbit to produces stunning pictures of Earth's surface.

Landsat 8 measures Earth's surfaces in the visible, near-infrared, short wave infrared and thermal infrared, with a moderate-resolution of 50ft to 328ft (15 to 100 metres).

Landsat 7, meanwhile, is on a mission to refresh the huge global archive of satellite photos, providing up-to-date and cloud-free images. It has an average resolution of 100ft to 328ft (30 to 100 metres).

Landsat 7 (left) is on a mission to refresh the huge global archive of satellite photos. On the right is the original Landsat, dubbed Earth Resources Technology satellite, or Landsat 1, which was launched on July 23, 1972

Landsat has provided the longest continuous space-based record of Earth's land in existence. Pictured is a timeline of different satellites