There may be far fewer galaxies further out in the universe then might be expected, according to a new study led by Michigan State University.
Over the years, the Hubble Space Telescope has allowed astronomers to look deep into the universe. The long view stirred theories of untold thousands of distant, faint galaxies. The new research, appearing in the current issue of the Astrophysical Journal Letters, however, offers a theory that reduces the estimated number of the most distant galaxies by 10 to 100 times.(more…)
Let’s all fist bump: Spiral galaxies like our own Milky Way appear to be much larger and more massive than previously believed, according to a new University of Colorado Boulder study by researchers using the Hubble Space Telescope.
CU-Boulder Professor John Stocke, study leader, said new observations with Hubble’s $70 million Cosmic Origins Spectrograph, or COS, designed by CU-Boulder show that normal spiral galaxies are surrounded by halos of gas that can extend to over 1 million light-years in diameter. The current estimated diameter of the Milky Way, for example, is about 100,000 light-years. One light-year is roughly 6 trillion miles. (more…)
University of Colorado Boulder astronomers targeting one of the brightest quasars glowing in the universe some 11 billion years ago say “sideline quasars” likely teamed up with it to heat abundant helium gas billions of years ago, preventing small galaxy formation.
CU-Boulder Professor Michael Shull and Research Associate David Syphers used the Hubble Space Telescope to look at the quasar — the brilliant core of an active galaxy that acted as a “lighthouse” for the observations — to better understand the conditions of the early universe. The scientists studied gaseous material between the telescope and the quasar with a $70 million ultraviolet spectrograph on Hubble designed by a team from CU-Boulder’s Center for Astrophysics and Space Astronomy. (more…)
Astronomers have witnessed for the first time a spiral galaxy in the early universe, billions of years before many other spiral galaxies formed. In findings reported July 19 in the journal Nature, the astronomers said they discovered it while using the Hubble Space Telescope to take pictures of about 300 very distant galaxies in the early universe and to study their properties. This distant spiral galaxy is being observed as it existed roughly three billion years after the Big Bang, and light from this part of the universe has been traveling to Earth for about 10.7 billion years.
“As you go back in time to the early universe, galaxies look really strange, clumpy and irregular, not symmetric,” said Alice Shapley, a UCLA associate professor of physics and astronomy, and co-author of the study. “The vast majority of old galaxies look like train wrecks. Our first thought was, why is this one so different, and so beautiful?” (more…)
Hosted by world-renowned astrophotographer Adam Block at the UA’s Mount Lemmon SkyCenter, a group of sky and astronomy enthusiasts watched Venus cross the sun from the highest vantage point in Southern Arizona.
On Nov. 24, 1639, in the tiny village of Much Hoole not far from Liverpool, England, a poor farmer’s son and self-taught astronomer affixed a sheet of paper in front of a makeshift telescope pointed at the sun and waited.
Thirty-five minutes before sunset, a dark, round spot appeared right next to the bright disc that was the sun’s face projected on the paper, and made Jeremiah Horrocks, only 20 years old at the time, the first known human to predict, observe and record a transit – the passage of a planet across the sun as seen from Earth.
Almost 373 years later, a group of sky enthusiasts is gathered beneath the dome of one of the University of Arizona’s observatories on Mount Lemmon just north of Tucson, Ariz. (more…)
*Astronomers watch a delayed broadcast of a powerful stellar eruption.*
Astronomers are watching the astronomical equivalent of streaming live video of a spectacular outburst from the unstable, behemoth double-star system Eta Carinae, which initially was seen on Earth nearly 170 years ago.
Dubbed the “Great Eruption,” the outburst lasted from 1837 to 1858 and caught the attention of sky-watchers at the time, including the British astronomer Sir John Herschel. He did not have the benefit of the imaging cameras and spectrographs that modern astronomers use to learn about stars, so we only have a historical record of the star’s visual brightness. (more…)
A team led by UCLA research astronomer Michael Rich has used a unique telescope to discover a previously unknown companion to the nearby galaxy NGC 4449, which is some 12.5 million light years from Earth. The newly discovered dwarf galaxy had escaped even the prying eyes of the Hubble Space Telescope.
The research is published Feb. 9 in the journal Nature.(more…)
A University of Exeter astrophysicist has shown what sunsets look like on planets outside our solar system.
He has worked out the colour of sunsets on two planets: HD 209458 b and HD 189733 b, known as ‘extrasolar planets’ because they are outside our solar system.
Extrasolar planets orbit stars, in a similar way to the Earth orbiting the Sun. Professor Frédéric Pont of the University of Exeter has used the extrasolar planets’ ‘transmission spectrum’, taken by the Hubble Space Telescope, to work out the colour of the ‘sunsets’ created by these stars.
Writing on the website ExoClimes.com, where he has posted the two sunset images he has produced, Professor Pont said: “Unlike its sister planet HD ’189, the planet HD ’209 (‘Osiris’) has a sunset that looks truly alien. The star is white outside the atmosphere, since its temperature is close to that of the Sun. It then acquires a bluish tinge as it sinks deeper, because the absorption by the broad wings of the neutral sodium lines (the spectral lines responsible for the gloomy orange of sodium street lighting) remove the red and orange from the star light. (more…)
