The Hubble Space Telescope: Revolutionizing Remote-Distance Measurements

So how do scientists today measure galactic velocities and distances? Gathering velocities from a broad sample of nearby and faraway galaxies is not that difficult--since the time of Edwin Hubble, redshift analysis has been a handy tool for that purpose. Measuring galactic distances, however, is another story.

A model of the Hubble Telescope

Before NASA launched the Hubble Space Telescope, ground telescopes helped scientists determine the distance to some nearby galaxies by measuring the brightness of certain parts of those galaxies. But earth-bound telescopes could not make such measurements for remote galaxies. This problem has been a significant stumbling block, since scientists need to gather measurements from a wide array of distant galaxies to compute a reliable estimate for the age of the universe.

And that’s where the Hubble Space Telescope comes in.

Hubble can accurately measure distances of galaxies as far as 108 million light years away, far surpassing the distance-measurement capabilities of ground telescopes. Hubble does this by measuring the brightness of certain objects found in remote galaxies, including blinking stars known as cepheids and exploded stars called type 1a supernovas.

Before the Hubble Space Telescope mined this critical information from remote galaxies, the limited galactic data available yielded very rough estimates of the age of the universe. In fact, as late as the early 1990s, estimates ranged widely between 10 and 20 billion years. In contrast, Hubble has allowed scientists today to calculate their most accurate estimate ever--a range between 12 and 16 billion years .

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