The Milky Way And Its Red Nebulae Hanging Over The Isaac Newton Telescope At La Palma // Jakob Sahner

Two spiral galaxies, NGC 6040 and NGC 6039, are merging together at the right side of this Hubble image. NGC 6039 is seen face-on and is circular in shape. NGC 6040 seems to lie in front of the first one. In the lower-left corner, cut off by the frame, the elliptical galaxy NGC 6041 — a central member of the galaxy cluster that Arp 122 resides in — appears as light radiating from a point. The color image was made from separate exposures taken in the visible and infrared regions

2023 September 28

The Deep Lagoon Image Credit & Copyright: Josep Drudis, Christian Sasse

Explanation: Ridges of glowing interstellar gas and dark dust clouds inhabit the turbulent, cosmic depths of the Lagoon Nebula. Also known as M8, The bright star forming region is about 5,000 light-years distant. It makes for a popular stop on telescopic tours of the constellation Sagittarius toward the center of our Milky Way Galaxy. Dominated by the telltale red emission of ionized hydrogen atoms recombining with stripped electrons, this deep telescopic view of the Lagoon’s central reaches is about 40 light-years across. The bright hourglass shape near the center of the frame is gas ionized and sculpted by energetic radiation and extreme stellar winds from a massive young star.

∞ Source: apod.nasa.gov/apod/ap230928.html

Laika: 1954-1957

Opportunity Rover: 2004-2019

Neptune's rings & moon Triton © Voyager 2

HOW DO ASTRONOMERS DETECT EXOPLANETS AND DETERMINE IF THEY COULD SUPPORT LIFE??

Blog#335

Wednesday, September 27th, 2023

Welcome back,

On March 21, NASA announced the confirmation of the 5,000th planet outside our Solar System. From scorching-hot gas giants nestled near their parent star to rocky worlds that may host water on their surface, there’s a variety for scientists to study.

But finding these strange new worlds is a science in itself.

We’ve only been able to definitively detect planets of any kind for a few decades, and even at that, there are challenges in detecting such a small object at that distance in even the most powerful telescopes.

Inverse spoke with Marie-Eve Naud, an exoplanet researcher and outreach coordinator for the University of Montreal’s Institute for Research on Exoplanets, to tell us more about how astronomers find these worlds and the considerations for each method.

While there are numerous methods, the ones cited below are the most common.

THE TRANSIT METHOD

Astronomers have discovered most exoplanets using the transit method, notably with NASA's Kepler telescope launched in 2009. This method observes planets as they pass in front of their stars, causing a slight dimming of starlight, which photometers can detect. This approach works best in space due to minimal atmospheric interference, favored by missions like ESA's Cheops and NASA's TESS.

To confirm exoplanets, multiple transits are necessary to rule out sunspots or dust as causes of light fluctuations. Typically, two or three transits are required to gather substantial data.

Once a planet is detected, astronomers can estimate its radius, while mass is often determined through the radial velocity method. The combination of mass and radius helps classify a planet as rocky or gaseous, impacting its potential habitability.

Factors like proximity to an active star and radiation levels also affect habitability assessments, as seen with TRAPPIST-1's uncertain habitability despite hosting seven Earth-sized planets in its habitable zone.

RADIAL-VELOCITY METHOD

The radial velocity method is commonly used to discover planets, particularly with instruments like HARPS at the European Southern Observatory’s La Silla 3.6m telescope in Chile.

Planets and stars both orbit around their center of mass. A star with a planet exhibits a slight motion. Multiple planets can lead to complex motions.

This method involves analyzing the star's spectrum. When the star approaches, its light shifts towards red due to compression. When it moves away, the light shifts towards blue.

The planet's motion slightly affects the star's spectrum, creating a "barcode" of the star.

The first detection of a planet around a Sun-like star using this method was in 1995 when Didier Queloz and Michel Mayor found 51 Pegasi b. Prior to that, in 1992, planets were detected around pulsar PSR B1257+12, using changes in the pulsar's radio signal. This showcases the diverse scientific approaches to discovering distant worlds.

Originally published on www.inverse.com

COMING UP!!

(Saturday, September 30th, 2023)

"WHAT IS THE BLOCK THEORY??"

The Seagull Nebula © Gianni Lacroce

Cosmic Delights and Distant Discoveries Unfold in ‘Astronomy Photographer of the Year 15’

NATIVE CARBON DIOXIDE FOUND ON JUPITER’S MOON EUROPA

Titan's high-level haze taken by Cassini on October 12, 2010.

Image credit: NASA/JPL/Space Science Institute. Edited by J. Major.