Thursday 9 January 2020

Diaries of an Aspiring Astrophysicist (DAS Astro) Podcast

Diaries of an Aspiring Astrophysicist

Episode 1: The last year has been weird

Episode 2: Cosmic Collisions and Gravitational Waves


Sunday 7 July 2019

NASA confirmed exoplanet table parameters and definitions




Database Column Name
Table Label
Description
0 pl_hostname Host Star Name Stellar name most commonly used in the literature.
1 pl_letter Planet Letter Letter assigned to the planetary component of a planetary system.
2 pl_name Planet Name Planet name most commonly used in the literature.
3 pl_discmethod Discovery Method Method by which the planet was first identified.
4 pl_controvflag Controversial Flag Flag indicating whether the confirmation status of a planet has been questioned in the published literature (1=yes, 0=no)
5 pl_pnum Number of Planets in System Number of planets in the planetary system.
6 pl_orbper Orbital Period (days) Time the planet takes to make a complete orbit around the host star or system.
7 pl_orbsmax Orbit Semi-Major Axis (AU) The longest radius of an elliptic orbit, or, for exoplanets detected via gravitational microlensing or direct imaging, the projected separation in the plane of the sky.
8 pl_orbeccen Eccentricity Amount by which the orbit of the planet deviates from a perfect circle.
9 pl_orbincl Inclination (deg) Angular distance of the orbital plane from the line of sight.
10 pl_bmassj Planet Mass or M*sin(i) [Jupiter mass] Best planet mass estimate available, in order of preference: Mass, M*sin(i)/sin(i), or M*sin(i), depending on availability, and measured in Jupiter masses. See Planet Mass M*sin(i) Provenance (pl_bmassprov) to determine which measure applies.
11 pl_bmassprov Planet Mass or M*sin(i) Provenance Provenance of the measurement of the best mass. Options are: Mass, M*sin(i)/sin(i), and M*sini.
12 pl_radj Planet Radius (Jupiter radii) Length of a line segment from the center of the planet to its surface, measured in units of radius of Jupiter.
13 pl_dens Planet Density (g/cm**3) Amount of mass per unit of volume of the planet.
14 pl_ttvflag TTV Flag Flag indicating if the planet orbit exhibits transit timing variations from another planet in the system (1=yes, 0=no).Note:Non-transiting planets discovered via the transit timing variations of another planet in the system will not have their TTV flag set, since they do not themselves demonstrate TTVs.
15 pl_kepflag Kepler Field Flag Flag indicating if the planetary system signature is present in data taken with the Kepler mission (1=yes, 0=no).
16 pl_k2flag K2 Mission Flag Flag indicating if the planetary system signature is present in data taken with the K2 Mission (1=yes, 0=no).
17 pl_nnotes Number of Notes Number of Notes associated with the planet. View all notes in the Confirmed Planet Overview page.
18 ra_str RA (sexagesimal) Right Ascension of the planetary system in sexagesimal format.
19 dec_str Dec (sexagesimal) Declination of the planetary system in sexagesimal notation.
20 ra RA (decimal degrees) Right Ascension of the planetary system in decimal degrees.
21 dec Dec (decimal degrees) Declination of the planetary system in decimal degrees.
22 st_dist Distance (pc) Distance to the planetary system in units of parsecs.
23 gaia_dist GaiaDistance [pc] Distance computed fromGaiaparallax.
24 st_optmag Optical Magnitude [mag] Brightness of the host star as measured using the V (Johnson) or the Kepler-band in units of magnitudes.
25 st_optband Optical Magnitude Band Band corresponding to the Optical Magnitude. Options are: V (Johnson) or Kepler-band.
26 gaia_gmag G-band (Gaia) [mag] Brightness of the host star as measuring using theGaiaband in units of magnitudes. Objects matched toGaiausing the Hipparcos or 2MASS IDs provided inGaiaDR2.
27 st_teff Effective Temperature (K) Temperature of the star as modeled by a black body emitting the same total amount of electromagnetic radiation.
28 st_mass Stellar Mass (solar mass) Amount of matter contained in the star, measured in units of masses of the Sun.
29 st_rad Stellar Radius (solar radii) Length of a line segment from the center of the star to its surface, measured in units of radius of the Sun.
30 rowupdate Date of Last Update Date of last update of the planet parameters.
31 pl_facility Discovery Facility Name of facility of planet discovery observations
33 pl_tranflag Planet Transit Flag Flag indicating if the planet transits its host star (1=yes, 0=no)
34 pl_rvflag Planet RV Flag Flag indicating if the planet host star exhibits radial velocity variations due to the planet (1=yes, 0=no)
35 pl_imgflag Planet Imaging Flag Flag indicating if the planet has been observed via imaging techniques (1=yes, 0=no)
36 pl_astflag Planet Astrometry Flag Flag indicating if the planet host star exhibits astrometrical variations due to the planet (1=yes, 0=no)
37 pl_omflag Orbital Modulation Flag Flag indicating whether the planet exhibits orbital modulations on the phase curve (1=yes, 0=no)
38 pl_cbflag Circumbinary Flag Flag indicating whether the planet orbits a binary system (1=yes, 0=no)
39 pl_angsep Calculated Angular Separation [mas] The calculated angular separation (semi-major axis/distance) between the star and the planet. This value is only calculated for systems with both a semi-major axis and a distance value.
40 pl_orbtper Time of Periastron (Julian Days) The time at which the orbiting body is at its closest approach to the star it orbits (i.e. is at periastron).
41 pl_orblper Longitude of Periastron (deg) The angular separation between the ascending node of the orbit and the location in the orbit of periastron.
42 pl_rvamp Radial Velocity Amplitude [m/s] Half the peak-to-peak amplitude of variability in the stellar radial velocity.
43 pl_eqt Planet Equilibrium Temperature [K] The equilibrium temperature of the planet as modeled by a black body heated only by its host star, or for directly imaged planets, the effective temperature of the planet required to match the measured luminosity if the planet were a black body.
44 pl_insol Insolation Flux [Earth flux] Insolation flux is another way to give the equilibrium temperature. It's given in units relative to those measured for the Earth from the Sun.
45 pl_massj Planet Mass (Jupiter mass) Amount of matter contained in the planet, measured in units of masses of Jupiter.
46 pl_msinij Planet M*sin(i) (Jupiter mass) Minimum mass of a planet as measured by radial velocity, measured in units of masses of Jupiter.
47 pl_masse Planet Mass (Earth mass) Amount of matter contained in the planet, measured in units of masses of the Earth.
48 pl_msinie Planet M*sini(i) [Earth mass] Minimum mass of a planet as measured by radial velocity, measured in units of masses of Earth.
49 pl_bmasse Planet Mass or M*sin(i) [Earth mass] Best planet mass estimate available, in order of preference: Mass, M*sin(i)/sin(i), or M*sin(i), depending on availability, and measured in Earth masses. See Planet Mass M*sin(i) Provenance (pl_bmassprov) to determine which measure applies.
50 pl_rade Planet Radius (Earth radii) Length of a line segment from the center of the planet to its surface, measured in units of radius of the Earth.
51 pl_rads Planet Radius (solar) Length of a line segment from the center of the planet to its surface, measured in units of radius of the Sun.
52 pl_trandep Transit Depth (percentage) The size of the relative flux decrement caused by the orbiting body transiting in front of the star.
53 pl_trandur Transit Duration (days) The length of time from the moment the planet begins to cross the stellar limb to the moment the planet finishes crossing the stellar limb.
54 pl_tranmid Transit Midpoint (Julian days) The time given by the average of the time the planet begins to cross the stellar limb and the time the planet finishes crossing the stellar limb.
55 pl_tsystemref Time System Reference
56 pl_imppar Impact Parameter The sky-projected distance between the center of the stellar disc and the center of the planet disc at conjunction, normalized by the stellar radius.
57 pl_occdep Occultation Depth Depth of occultation of secondary eclipse
58 pl_ratdor Planet-Star Distance over Star Radius The distance between the planet and the star at mid-transit divided by the stellar radius. For the case of zero orbital eccentricity, the distance at mid-transit is the semi-major axis of the planetary orbit.
59 pl_ratror Planet-Star Radius Ratio The planet radius divided by the stellar radius
60 pl_def_refname Default Reference Reference for publication used for default parameter
61 pl_disc Year of Discovery Year the planet was discovered
62 pl_disc_refname Discovery Reference Reference name for discovery publication
63 pl_locale Discovery Locale Location of observation of planet discovery (Ground or Space)
64 pl_telescope Discovery Telescope Name of telescope of planet discovery observations
65 pl_instrument Discovery Instrument Name of instrument of planet discovery observations
66 pl_status Status Status of the planet (1 = announced, 2 = submitted, 3 = accepted, 0 = retracted).
67 pl_mnum Number of Moons in System Number of moons detected in the planetary system.
68 pl_st_npar Number of Stellar and Planet Parameters Number of Stellar and Planet Parameters
69 pl_st_nref Number of Stellar and Planet References Number of Stellar and Planet References
70 pl_pelink Link to Exoplanet Encyclopaedia It links to the planet page in the Exoplanet Encyclopaedia.
71 pl_edelink Link to Exoplanet Data Explorer It links to the planet page in Exoplanet Data Explorer.
72 pl_publ_date Publication Date Publication Date of the planet discovery referee publication.
74 hd_name HD Name Name of the star as given by the Henry Draper Catalog.
75 hip_name HIP Name Name of the star as given by the Hipparcos Catalog.
76 st_rah RA (hours) Right Ascension of the planetary system in decimal hours.
77 st_glon Galactic Longitude (deg) Galactic longitude of the planetary system in units of decimal degrees.
78 st_glat Galactic Latitude (deg) Galactic latitude of the planetary system in units of decimal degrees.
79 st_elon Ecliptic Longitude (deg) Ecliptic longitude of the planetary system in units of decimal degrees.
80 st_elat Ecliptic Latitude (deg) Ecliptic latitude of the planetary system in units of decimal degrees.
81 st_plx Parallax (mas) Difference in the angular position of a star as measured at two opposite positions within the Earth's orbit.
82 gaia_plx GaiaParallax [mas] GaiaDR2 difference in the angular position of a star as measured at two opposite positions within the Earth's orbit.
83 st_pmra RA Proper Motion (mas/yr) Angular change in right ascension over time as seen from the center of mass of the Solar System.
84 st_pmdec Dec Proper Motion (mas/yr) Angular change in declination over time as seen from the center of mass of the Solar System.
85 st_pm Total Proper Motion (mas/yr) Angular change in position over time as seen from the center of mass of the Solar System.
86 gaia_pmra GaiaProper Motion (RA) [mas/yr] GaiaDR2 angular change in right ascension over time as seen from the center of mass of the Solar System.
87 gaia_pmdec GaiaProper Motion (Dec) [mas/yr] GaiaDR2 angular change in declination over time as seen from the center of mass of the Solar System.
88 gaia_pm GaiaTotal Proper Motion [mas/yr] GaiaDR2 total proper motion computed from the RA and Dec.
89 st_radv Radial Velocity (km/sec) Velocity of the star in the direction of the line of sight.
90 st_spstr Spectral Type Classification of the star based on their spectral characteristics following the Morgan-Keenan system.
91 st_logg Stellar Surface Gravity Gravitational acceleration experienced at the stellar surface.
92 st_lum Stellar Luminosity [log(solar)] Amount of energy emitted by a star per unit time, measured in units of solar luminosities.
93 st_dens Stellar Density [g/cm**3] Amount of mass per unit of volume of the star.
94 st_metfe Stellar Metallicity (dex) Measurement of the metal content of the photosphere of the star as compared to the hydrogen content.
95 st_metratio Metallicity Ratio Ratio for the Metallicity Value ([Fe/H] denotes iron abundance, [M/H] refers to a general metal content)
96 st_age Stellar Age [Gyr] The age of the host star.
97 st_vsini Rotational Velocity v*sin(i) [km/s] Rotational velocity at the equator of the star multiplied by the sine of the inclination.
98 st_acts Stellar Activity Index (S-Index) Chromospheric activity as measured by the S-index (ratio of the emission of the H and K Ca lines to that in nearby continuum).
99 st_actr Stellar Activity Log (R'HK) Chromospheric activity as measured by the log(R' HK) index, with is based on the S-index, but excludes the photospheric component in the Ca lines.
100 st_actlx x-ray Activity (Lx)" Stellar activity as measured by the total luminosity in X-rays.
101 swasp_id SWASP Identifier Name of the star as given by the SuperWASP (Wide Angle Search for Planets) project.
102 st_nts Number of Time Series Number of literature time series available for this star in the NASA Exoplanet Archive
103 st_nplc Number of Planet Transit Light Curves Number of literature transit light curves available for this star in the NASA Exoplanet Archive.
104 st_nglc Number of General Light Curves Number of Hipparcos light curves available for this star in the NASA Exoplanet Archive.
105 st_nrvc Number of Radial Velocity Time Series Number of literature radial velocity curves available for this star in the NASA Exoplanet Archive.
106 st_naxa Number of Amateur Light Curves Number of literature amateur light curves available for this star in the NASA Exoplanet Archive.
107 st_nimg Number of Images Number of literature images available for this star in the NASA Exoplanet Archive.
108 st_nspec Number of Spectra Number of literature of spectra available for this star in the NASA Exoplanet Archive.
110 st_uj U-band (Johnson) [mag] Brightness of the host star as measured using the U (Johnson) band in units of magnitudes.
111 st_vj V-band (Johnson) [mag] Brightness of the host star as measured using the V (Johnson) band in units of magnitudes.
112 st_bj B-band (Johnson) [mag] Brightness of the host star as measured using the B (Johnson) band in units of magnitudes.
113 st_rc R-band (Cousins) [mag] Brightness of the host star as measured using the R (Cousins) band in units of magnitudes.
114 st_ic I-band (Cousins) [mag] Brightness of the host star as measured using the I (Cousins) band in units of magnitudes.
115 st_j J-band (2MASS) [mag] Brightness of the host star as measured using the J (2MASS) band in units of magnitudes.
116 st_h H-band (2MASS) [mag] Brightness of the host star as measured using the H (2MASS) band in units of magnitudes.
117 st_k Ks-band (2MASS) [mag] Brightness of the host star as measured using the K (2MASS) band in units of magnitudes.
118 st_wise1 WISE 3.4um [mag] Brightness of the host star as measured using the 3.4um (WISE) band in units of magnitudes.
119 st_wise2 WISE 4.6um [mag] Brightness of the host star as measured using the 4.6um (WISE) band in units of magnitudes.
120 st_wise3 WISE 12.um [mag] Brightness of the host star as measured using the 12.um (WISE) band in units of magnitudes.
121 st_wise4 WISE 22.um [mag] Brightness of the host star as measured using the 22.um (WISE) band in units of magnitudes.
122 st_irac1 IRAC 3.6um [mag] Brightness of the host star as measured using the 3.6um (IRAC) band in units of magnitudes.
123 st_irac2 IRAC 4.5um [mag] Brightness of the host star as measured using the 4.5um (IRAC) band in units of magnitudes.
124 st_irac3 IRAC 5.8um [mag] Brightness of the host star as measured using the 5.8um (IRAC) band in units of magnitudes.
125 st_irac4 IRAC 8.0um [mag] Brightness of the host star as measured using the 8.0um (IRAC) band in units of magnitudes.
126 st_mips1 MIPS 24um [mag] Brightness of the host star as measured using the 24um (MIPS) band in units of magnitudes.
127 st_mips2 MIPS 70um [mag] Brightness of the host star as measured using the 70um (MIPS) band in units of magnitudes.
128 st_mips3 MIPS 160um [mag] Brightness of the host star as measured using the 160um (MIPS) band in units of magnitudes.
129 st_iras1 IRAS 12um [Jy] Brightness of the host star as measured using the 12um (IRAS) band in units of Jy.
130 st_iras2 IRAS 25um [Jy] Brightness of the host star as measured using the 25um (IRAS) band in units of Jy.
131 st_iras3 IRAS 60um [Jy] Brightness of the host star as measured using the 60um (IRAS) band in units of Jy.
132 st_iras4 IRAS 100um [Jy] Brightness of the host star as measured using the 100um (IRAS) band in units of Jy.
133 st_photn Number of Photometry Measurements Number of photometry measurements available for this star in the NASA Exoplanet Archive.
135 st_umbj U-B (Johnson) [mag] Color of the star as measured by the difference between U and B (Johnson) bands.
136 st_bmvj B-V (Johnson) [mag] Color of the star as measured by the difference between B and V (Johnson) bands.
137 st_vjmic V-I (Johnson-Cousins) [mag] Color of the star as measured by the difference between V (Johnson) and I (Cousins) bands.
138 st_vjmrc V-R (Johnson-Cousins) [mag] Color of the star as measured by the difference between V (Johnson) and R (Cousins) bands.
139 st_jmh2 J-H (2MASS) [mag] Color of the star as measured by the difference between J and H (2MASS) bands.
140 st_hmk2 H-Ks (2MASS) [mag] Color of the star as measured by the difference between H and K (2MASS) bands.
141 st_jmk2 J-Ks (2MASS) [mag] Color of the star as measured by the difference between K and K (2MASS) bands.
142 st_bmy b-y (Stromgren) [mag] Color of the star as measured by the difference between b and y (Stromgren) bands.
143 st_m1 m1 (Stromgren) [mag] Color of the star as measured by the m1 (Stromgren) system.
144 st_c1 c1 (Stromgren) [mag] Color of the star as measured by the c1 (Stromgren) system.
145 st_colorn Number of Color Measurements Number of color measurements available for this star in the NASA Exoplanet Archive.
147

Monday 1 July 2019

Visualizing confirmed exoplanet detection with Tableau.


Every human child has at one point in their lives dreamed of venturing to the stars and exploring other worlds. For some of those children those dreams manifest themselves in the form trance music played in cave on the southern hemisphere during the longest night of the year, the winter solstice.

For others it manifests as a desire to pursue a career in radio astronomy. I'm on the path of the latter.

Here is proof:


Can't stop this Sagan in the makin. Radio astronomy is awesome.

The search for Exoplanets.


In the last 20 years humanity has begun an incredible preliminary exploration of nearby solar systems that may contain worlds in orbit around other stars.

Using data visualization software Tableau Public as part of my semester break project I have compiled some interesting perspectives on the variety of confirmed exoplanets that exist outside our solar systems, thus producing a series of info-graphics I call the "Infographica Galactica" which is a play on words on the "Encyclopedia Galactica"

This blog post details the development of this project.

Now, radio astronomy and planetary science are two different disciplines. One deals with light at low frequency and the other deals with wandering bodies in orbit around stars but both are connected by the practice of data mining and the art of knowledge discovery and that is exactly the type of approach that will be taken in this project.

*literature review on the planets.

The search for planets beyond our solar system goes hand in hand with the search for extraterrestrial life. So far we only have one model to go on to study the emergence of life in the entire Universe and that is planet Earth in our own solar system. (The verdicts on Mars and Europa have yet to be decided). Therefore, the search for exoplanets boils down to the quest of looking for planets that are "Earth Size" and "Earth like"

We must then establish the distinction between planets that are "Earth Size" and "Earth Like"

NASA Exoplanet Database. the 4,000 worlds


NASA keeps an database archive of confirmed exoplanets. So far there have been 4,000 worlds known without a doubt to exist beyond our solar system. A full list of the planets can be downloaded which makes for great exercise in data mining depending on what you are looking for.

There is separate table available that details the definition of each parameter in the confirmed planets table:

https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=planets



There is separate table available that details the definition of each attribute in the confirmed planets table: 



As part of literature review I need to understand what each term does and whether it has any significance for visualization. There are 5 tables  detailing terms on the confirmed exoplanet table. Each table corresponds to a different characteristic.

  • Default Column
  • Planet Column
  • Stellar Column
  • Photometry Column
  • Colour Column

I could do it manually by copying each term from the website into the excel table that I have on my laptop. But as any good programmer knows:

"Anything you have to do repetitively more than 3 times can be automated."

So I scraped it using Beautiful Soup. A cursory glance at the terms shows the following




Code is available on github: https://github.com/coderXmachina2

The Draft of my Infographica




Wednesday 15 May 2019

How Pulsar Timing Arrays Work

Best Explanation so far for how a Pulsar Timing Array Works, and it makes it look more analogous to an Interferometer which is sweet as.


Tuesday 7 May 2019

Hippo Poo Vital for Health of East Africa's Rivers

Hippo poo vital for ecosystem balance


I have good shit

There was a piece of News recently about how hippo feces acted as a vital carrier of Nutrients for rivers in East Africa. The large (and adorable) land fauna would eat copious amount of grass and just chill out with the herd in communal hippo pools where they would excrete the grass they had eaten.

The hippo feces contains a large amount of Silicon extracted from the grass that is vital to the health of tiny bacteria called diatoms that live further downstream all the way to Lake Victoria, the largest lake in Africa. This tiny bacteria forms the foundational basis of the diet and food chain of the Mara River in Africa and other rivers that flow into Lake Victoria.

The diatom bacteria are also responsible for carbon sequestration in the environment, that is the act of removing CO2 from the environment. CO2 is a greenhouse gas. Something that if we have too much of in the atmosphere... we die.

I shit you not

Hippo Poo makes the Mara River go round

Without a thriving bacterial community the environmental balance  in the area would be disastrously upset. Fish all along the food chain can't get their nutrition and a dangerous type of life-suffocating bacteria called cyanobacteria will grow to excess causing the emergence of environmental dead zones. That sounds scary.

In the light of recent catastrophes in nearby Mozambique it paints a bleak picture of the future.

The hippo population has suffered a decrease in the last decade and the numbers are projected to further drop but the actions we carry out on now will decide the fate of the hippos and the Mara River. There is still time to stop the key from turning. Once it turns there is no turning back.

DIatoms in a Psychedelic Universe. We are all connected
It makes me think about this little image here. Credits to Annis Pratt who led me to it.


And the line from the Fourth Hindu Veda:

Whatever I dig from you, O Earth
May your mantle grow back again quickly
O Earth, Purifier, may we never injure you

Sincerely,
SonOfTerra92

Saturday 27 April 2019

Why should we bother looking for Gravitational Waves?

26/4/2019 mid sem Holiday is almost up. I Better get started on that ASTR 800 (Advanced Topics in Astrophysics) paper.



Break is over, better get started on that term paper.

So I want to talk about Gravitational Waves, more so the importance of finding gravitational waves.

Why do we need to find these elusive ripples of propagating space time called Gravitational Waves?

For a long time Gravitational Waves seemed to be secluded within the realm of theoretical physics. The idea was born out of the mind of Einstein while the experimentalists in the room which included Richard Feynman and Joe Weber could only dream of detecting them. Some of those early  experimentalists although daring in the quest for gravitational waves are no longer with us, were not able to make it to witness the progress we have made today.

But the first Ligo Gravitational Wave observation happened in 2016 and we can now pinpoint their origins to Supermassive Black Hole Binaries (SMBHB) and Neutron Star Binaries (NSB). Wherever there are really dense astronomical objects orbiting each other in an inspriling cosmic death dance. That is where the origin of gravitational waves can be pinpointed to.


In-fact these events are responsible for the formation of heavier elements in the Universe like Gold and Platinum. So you are essentially buying for your spouse a briproduct of the most violent collisions in the Universe.... just like my relationships.

But why do Astronomers have a vested interest in detecting these gravitational waves?

Well that is an interesting question actually. I mean are not observations in the EM domain enough to learn us all we can about the Universe that we live in and the Cosmos from which we spring?

Well, I can tell you that the answer to that is No. Because of something called Multi Messenger Astronomy.

We live in the age of Mutli-Messenger Astronomy (MMA) which is this idea that we can acquire much more information about the universe by looking at signals that reach us in different ways. Here are the 4 ways that information about the Universe can reach us.

  • EM - Light. The classic Medium of Discovery. From Planets to Pulsars this is how its been done since back in the day.
  • Gravitational Waves - Ripples of Propagating space time. These can tell us about the merging of really dense objects in the Universe. Black Holes and Netutron Stars
  • Neutrinos - Elusive Tiny Particles travelling at the speed of light.
  • Cosmic Rays - High Energy Particles. Can tell us about  Gamma Ray bursts

Some of things out there may be detectable by the many different media, others in singularly different ones. but there is a wealth of information that can be conveyed by analyzing the same cosmological phenomena in the different messenger media.

One example is how the Gravitational Waves detected by LIGO are quickly followed up by observations by Radio Telescopes. etc.

But what really convinced me about MMA  surrounds some discoveries that happened around the time of my birth (1992). That is the discovery of PSR B 1257 + 12 and the planets that surround it. DraugrPoltergeist and Phobetor.

I wonder if it will have an atmosphere. Not that we really need one if we ever get to explore it. I figure we'll carry our own atmosphere with us.

These 3 planets orbit the husk of a star that went supernova a long time ago. That star is survived today as a pulsar that periodically emits beams of electromagnetic radiation  The planets were discovered by measuring the variation in Doppler shift of pulsation Period.

This planet marks the discovery of an extrasolar planet via means of Pulsar Timing.  One of the worlds was discovered to be twice the size of the moon at 0.02 Earth Mass, the smallest planet ever to be discovered. In all the planets discovered by the Kepler mission in the modern age. Pulsar Timing in 1992 (the year that I was born) revealed to us a world in a category of its own. A tiny little speck orbiting a Pulsar.

That remarkable discovery was made via an indirect observation by studying subtle changes in the propagation of light. we didn't see the planet optically but implied its existence by looking at the effect it had on the pulsar signal, thus confirming its existence.

Now extend that to Gravitational Waves and the information they carry, and the things we might come to learn of when we detect Grav Waves. What new wonders undreamt of in our own time would will we discover by studying gravitational waves? 

Lets find out...







Diaries of an Aspiring Astrophysicist (DAS Astro) Podcast

Diaries of an Aspiring Astrophysicist Episode 1: The last year has been weird Episode 2: Cosmic Collisions and Gravitational Wa...