התחל במצב לא מקוון עם האפליקציה Player FM !
E32 # HOW DARK IS SPACE?
Manage episode 287316644 series 2884538
NEW MEASUREMENTS OF THE SKY’S BLACKNESS SHOW MORE LIGHT THAN CAN BE ACCOUNTED FOR BY KNOWN GALAXIES.
How dark is the sky, and what does that tell us about the number of galaxies in the visible universe? Astronomers can estimate the total number of galaxies by counting everything visible in a Hubble deep field and then multiplying them by the total area of the sky. But other galaxies are too faint and distant to directly detect. Yet while we can’t count them, their light suffuses space with a feeble glow.
To measure that glow, astronomers have to escape the inner solar system and its light pollution, caused by sunlight reflecting off dust. A team of scientists has used observations by NASA’s New Horizons mission to Pluto and the Kuiper Belt to determine the brightness of this cosmic optical background. Their result sets an upper limit to the starlight emitted by faint, unresolved galaxies, showing that there is about twice as much optical light permeating space as can be accounted for by all known galaxies.
Credit: NASA/STScI
47 פרקים
Manage episode 287316644 series 2884538
NEW MEASUREMENTS OF THE SKY’S BLACKNESS SHOW MORE LIGHT THAN CAN BE ACCOUNTED FOR BY KNOWN GALAXIES.
How dark is the sky, and what does that tell us about the number of galaxies in the visible universe? Astronomers can estimate the total number of galaxies by counting everything visible in a Hubble deep field and then multiplying them by the total area of the sky. But other galaxies are too faint and distant to directly detect. Yet while we can’t count them, their light suffuses space with a feeble glow.
To measure that glow, astronomers have to escape the inner solar system and its light pollution, caused by sunlight reflecting off dust. A team of scientists has used observations by NASA’s New Horizons mission to Pluto and the Kuiper Belt to determine the brightness of this cosmic optical background. Their result sets an upper limit to the starlight emitted by faint, unresolved galaxies, showing that there is about twice as much optical light permeating space as can be accounted for by all known galaxies.
Credit: NASA/STScI
47 פרקים
כל הפרקים
×ברוכים הבאים אל Player FM!
Player FM סורק את האינטרנט עבור פודקאסטים באיכות גבוהה בשבילכם כדי שתהנו מהם כרגע. זה יישום הפודקאסט הטוב ביותר והוא עובד על אנדרואיד, iPhone ואינטרנט. הירשמו לסנכרון מנויים במכשירים שונים.