Are there billions of stars

This means that we cannot see any stars farther than about Within Although these are rough estimates, using these numbers we might imagine there are The number is so large we usually write it in a special way. The number is 1 , which has 24 zeros, so we write it as 10 About how many stars are in space? Answer 1: There are about 1,,,,,,, stars in space, or about 10 raised to the 21 10 21 power, roughly.

Answer 2: This is a fantastic question, and one that is difficult to answer! ESA's infrared space observatory Herschel has made an important contribution by 'counting' galaxies in the infrared, and measuring their luminosity in this range — something never before attempted. Knowing how fast stars form can bring more certainty to calculations. Herschel has also charted the formation rate of stars throughout cosmic history.

If you can estimate the rate at which stars have formed, you will be able to estimate how many stars there are in the Universe today. In , an image from the Hubble Space Telescope HST suggested that star formation had reached a peak at roughly seven thousand million years ago. Recently, however, astronomers have thought again.

The Hubble Deep Field image was taken at optical wavelengths and there is now some evidence that a lot of early star formation was hidden by thick dust clouds. Dust clouds block the stars from view and convert their light into infrared radiation, making them invisible to the HST.

But Herschel could peer into this previously hidden Universe at infrared wavelengths, revealing many more stars then ever seen before. Soon Gaia will launch, which will study one thousand million stars in our Milky Way. It will build on the legacy of the Hipparchus mission, which pinpointed the positions of more than one hundred thousand stars to high precision, and more than one million stars to lesser precision.

Astronomers had estimated that the observable universe has more than billion galaxies. The Milky Way is a titan compared to abundant but faint dwarf galaxies, and it in turn is dwarfed by rare giant elliptical galaxies, which can be 20 times more massive.

By measuring the number and luminosity of observable galaxies, astronomers put current estimates of the total stellar population at roughly 70 billion trillion 7 x 10 However, those estimates are dependent on the sensitivity of current telescopes.

More recent estimates have upped the number of galaxies in the observable universe to 2 trillion, though many of these are tiny, fluffy galaxies with fewer stars. If the typical galaxy had billion stars, then there would be 2 x 10 23 stars in the observable universe, three times as much as earlier estimates. But even this is still probably an underestimate, as more sensitive telescopes will continue to reveal fainter galaxies and stars. In large, light-polluted cities, only a few dozen of the brightest stars may be visible - though that doesn't mean there's nothing to observe from a city.

But in a clear, dark sky, a couple thousand stars become visible to the unaided eye. If you tabulate all stars visible down to magnitude 6. Since you can only see half the sky at any time, that means there are as many as 4, stars visible in your sky tonight. And as we continue to learn, all of these stars seem to have planets.